diff --git a/src/Logic/State/LayerState.ts b/src/Logic/State/LayerState.ts
index d611f91322..c1e9578ce6 100644
--- a/src/Logic/State/LayerState.ts
+++ b/src/Logic/State/LayerState.ts
@@ -184,9 +184,7 @@ export default class LayerState {
                 ", but this layer was not loaded"
             )
         }
-        console.warn(
-            "Linking filter and isDisplayed-states of " + layer.id + " and " + layer.filterIsSameAs
-        )
+        // We make a shallow copy, reusing the same underlying stores
         const copy = new FilteredLayer(layer, toReuse.appliedFilters, toReuse.isDisplayed)
         filteredLayers.set(layer.id, copy)
     }
diff --git a/src/Models/ThemeConfig/LayerConfig.ts b/src/Models/ThemeConfig/LayerConfig.ts
index 8504b4fff9..9039b94ee3 100644
--- a/src/Models/ThemeConfig/LayerConfig.ts
+++ b/src/Models/ThemeConfig/LayerConfig.ts
@@ -78,7 +78,11 @@ export default class LayerConfig extends WithContextLoader {
      */
     private readonly _basedOn: string | undefined
 
-    constructor(json: LayerConfigJson, context?: string, official: boolean = true) {
+    constructor(json: LayerConfigJson,
+                context?: string,
+                official: boolean = true,
+                allLayers?: LayerConfigJson[],
+    ) {
         context = context + "." + json?.id
         const translationContext = "layers:" + json.id
         super(json, context)
@@ -109,7 +113,7 @@ export default class LayerConfig extends WithContextLoader {
                     mercatorCrs: json.source["mercatorCrs"],
                     idKey: json.source["idKey"],
                 },
-                json.id
+                json.id,
             )
         }
 
@@ -129,7 +133,7 @@ export default class LayerConfig extends WithContextLoader {
         if (json.calculatedTags !== undefined) {
             if (!official) {
                 console.warn(
-                    `Unofficial theme ${this.id} with custom javascript! This is a security risk`
+                    `Unofficial theme ${this.id} with custom javascript! This is a security risk`,
                 )
             }
             this.calculatedTags = []
@@ -199,7 +203,7 @@ export default class LayerConfig extends WithContextLoader {
                 tags: pr.tags.map((t) => TagUtils.SimpleTag(t)),
                 description: Translations.T(
                     pr.description,
-                    `${translationContext}.presets.${i}.description`
+                    `${translationContext}.presets.${i}.description`,
                 ),
                 preciseInput: preciseInput,
                 exampleImages: pr.exampleImages,
@@ -213,7 +217,7 @@ export default class LayerConfig extends WithContextLoader {
 
         if (json.lineRendering) {
             this.lineRendering = Utils.NoNull(json.lineRendering).map(
-                (r, i) => new LineRenderingConfig(r, `${context}[${i}]`)
+                (r, i) => new LineRenderingConfig(r, `${context}[${i}]`),
             )
         } else {
             this.lineRendering = []
@@ -221,7 +225,7 @@ export default class LayerConfig extends WithContextLoader {
 
         if (json.pointRendering) {
             this.mapRendering = Utils.NoNull(json.pointRendering).map(
-                (r, i) => new PointRenderingConfig(r, `${context}[${i}](${this.id})`)
+                (r, i) => new PointRenderingConfig(r, `${context}[${i}](${this.id})`),
             )
         } else {
             this.mapRendering = []
@@ -233,7 +237,7 @@ export default class LayerConfig extends WithContextLoader {
                     r.location.has("centroid") ||
                     r.location.has("projected_centerpoint") ||
                     r.location.has("start") ||
-                    r.location.has("end")
+                    r.location.has("end"),
             )
 
             if (
@@ -255,7 +259,7 @@ export default class LayerConfig extends WithContextLoader {
                 Constants.priviliged_layers.indexOf(<any>this.id) < 0 &&
                 this.source !== null /*library layer*/ &&
                 !this.source?.geojsonSource?.startsWith(
-                    "https://api.openstreetmap.org/api/0.6/notes.json"
+                    "https://api.openstreetmap.org/api/0.6/notes.json",
                 )
             ) {
                 throw (
@@ -274,7 +278,7 @@ export default class LayerConfig extends WithContextLoader {
                     typeof tr !== "string" &&
                     tr["builtin"] === undefined &&
                     tr["id"] === undefined &&
-                    tr["rewrite"] === undefined
+                    tr["rewrite"] === undefined,
             ) ?? []
         if (missingIds?.length > 0 && official) {
             console.error("Some tagRenderings of", this.id, "are missing an id:", missingIds)
@@ -285,8 +289,8 @@ export default class LayerConfig extends WithContextLoader {
             (tr, i) =>
                 new TagRenderingConfig(
                     <QuestionableTagRenderingConfigJson>tr,
-                    this.id + ".tagRenderings[" + i + "]"
-                )
+                    this.id + ".tagRenderings[" + i + "]",
+                ),
         )
         if (json.units !== undefined && !Array.isArray(json.units)) {
             throw (
@@ -296,22 +300,33 @@ export default class LayerConfig extends WithContextLoader {
             )
         }
         this.units = (json.units ?? []).flatMap((unitJson, i) =>
-            Unit.fromJson(unitJson, this.tagRenderings, `${context}.unit[${i}]`)
+            Unit.fromJson(unitJson, this.tagRenderings, `${context}.unit[${i}]`),
         )
+        {
+            let filter = json.filter
+
+            while (
+                filter !== undefined &&
+                filter !== null &&
+                filter["sameAs"] !== undefined
+            ) {
+                const targetLayerName = filter["sameAs"]
+                this.filterIsSameAs = targetLayerName
+                const targetLayer = allLayers.find(l => l.id === targetLayerName)
+                if(!targetLayer){
+                    throw "Target layer "+targetLayerName+" not found in this theme"
+                }
+                filter = targetLayer?.filter
+            }
 
-        if (
-            json.filter !== undefined &&
-            json.filter !== null &&
-            json.filter["sameAs"] !== undefined
-        ) {
-            this.filterIsSameAs = json.filter["sameAs"]
             this.filters = []
-        } else {
-            this.filters = (<FilterConfigJson[]>json.filter ?? [])
-                .filter((f) => typeof f !== "string")
-                .map((option, i) => {
-                    return new FilterConfig(option, `layers:${this.id}.filter.${i}`)
-                })
+            {
+                this.filters = (<FilterConfigJson[]>filter ?? [])
+                    .filter((f) => typeof f !== "string")
+                    .map((option, i) => {
+                        return new FilterConfig(option, `layers:${this.id}.filter.${i}`)
+                    })
+            }
         }
 
         {
@@ -358,7 +373,7 @@ export default class LayerConfig extends WithContextLoader {
         }
         this.popupInFloatover = json.popupInFloatover ?? false
         this.baseTags = TagUtils.changeAsProperties(
-            this.source?.osmTags?.asChange({ id: "node/-1" }) ?? [{ k: "id", v: "node/-1" }]
+            this.source?.osmTags?.asChange({ id: "node/-1" }) ?? [{ k: "id", v: "node/-1" }],
         )
     }
 
@@ -368,6 +383,7 @@ export default class LayerConfig extends WithContextLoader {
         }
         return this.mapRendering.some((r) => r.location.has("point"))
     }
+
     public GenerateDocumentation(
         usedInThemes: string[],
         layerIsNeededBy?: Map<string, string[]>,
@@ -377,7 +393,7 @@ export default class LayerConfig extends WithContextLoader {
             neededLayer: string
         }[] = [],
         addedByDefault = false,
-        canBeIncluded = true
+        canBeIncluded = true,
     ): string {
         const extraProps: string[] = []
         extraProps.push("This layer is shown at zoomlevel **" + this.minzoom + "** and higher")
@@ -385,32 +401,32 @@ export default class LayerConfig extends WithContextLoader {
         if (canBeIncluded) {
             if (addedByDefault) {
                 extraProps.push(
-                    "**This layer is included automatically in every theme. This layer might contain no points**"
+                    "**This layer is included automatically in every theme. This layer might contain no points**",
                 )
             }
             if (this.shownByDefault === false) {
                 extraProps.push(
-                    "This layer is not visible by default and must be enabled in the filter by the user. "
+                    "This layer is not visible by default and must be enabled in the filter by the user. ",
                 )
             }
             if (this.title === undefined) {
                 extraProps.push(
-                    "Elements don't have a title set and cannot be toggled nor will they show up in the dashboard. If you import this layer in your theme, override `title` to make this toggleable."
+                    "Elements don't have a title set and cannot be toggled nor will they show up in the dashboard. If you import this layer in your theme, override `title` to make this toggleable.",
                 )
             }
             if (this.name === undefined && this.shownByDefault === false) {
                 extraProps.push(
-                    "This layer is not visible by default and the visibility cannot be toggled, effectively resulting in a fully hidden layer. This can be useful, e.g. to calculate some metatags. If you want to render this layer (e.g. for debugging), enable it by setting the URL-parameter layer-<id>=true"
+                    "This layer is not visible by default and the visibility cannot be toggled, effectively resulting in a fully hidden layer. This can be useful, e.g. to calculate some metatags. If you want to render this layer (e.g. for debugging), enable it by setting the URL-parameter layer-<id>=true",
                 )
             }
             if (this.name === undefined) {
                 extraProps.push(
-                    "Not visible in the layer selection by default. If you want to make this layer toggable, override `name`"
+                    "Not visible in the layer selection by default. If you want to make this layer toggable, override `name`",
                 )
             }
             if (this.mapRendering.length === 0) {
                 extraProps.push(
-                    "Not rendered on the map by default. If you want to rendering this on the map, override `mapRenderings`"
+                    "Not rendered on the map by default. If you want to rendering this on the map, override `mapRenderings`",
                 )
             }
 
@@ -420,12 +436,12 @@ export default class LayerConfig extends WithContextLoader {
                         "<img src='../warning.svg' height='1rem'/>",
                         "This layer is loaded from an external source, namely ",
                         "`" + this.source.geojsonSource + "`",
-                    ].join("\n\n")
+                    ].join("\n\n"),
                 )
             }
         } else {
             extraProps.push(
-                "This layer can **not** be included in a theme. It is solely used by [special renderings](SpecialRenderings.md) showing a minimap with custom data."
+                "This layer can **not** be included in a theme. It is solely used by [special renderings](SpecialRenderings.md) showing a minimap with custom data.",
             )
         }
 
@@ -435,7 +451,7 @@ export default class LayerConfig extends WithContextLoader {
                 usingLayer = [
                     "## Themes using this layer",
                     MarkdownUtils.list(
-                        (usedInThemes ?? []).map((id) => `[${id}](https://mapcomplete.org/${id})`)
+                        (usedInThemes ?? []).map((id) => `[${id}](https://mapcomplete.org/${id})`),
                     ),
                 ]
             } else if (this.source !== null) {
@@ -451,7 +467,7 @@ export default class LayerConfig extends WithContextLoader {
                     " into the layout as it depends on it: ",
                     dep.reason,
                     "(" + dep.context + ")",
-                ].join(" ")
+                ].join(" "),
             )
         }
 
@@ -478,7 +494,7 @@ export default class LayerConfig extends WithContextLoader {
                             new And(preset.tags).asHumanString(true) +
                             snaps
                         )
-                    })
+                    }),
                 ),
             ]
         }
@@ -486,8 +502,8 @@ export default class LayerConfig extends WithContextLoader {
         for (const revDep of Utils.Dedup(layerIsNeededBy?.get(this.id) ?? [])) {
             extraProps.push(
                 ["This layer is needed as dependency for layer", `[${revDep}](#${revDep})`].join(
-                    " "
-                )
+                    " ",
+                ),
             )
         }
 
@@ -498,10 +514,10 @@ export default class LayerConfig extends WithContextLoader {
                 .filter((values) => values.key !== "id")
                 .map((values) => {
                     const embedded: string[] = values.values?.map((v) =>
-                        Link.OsmWiki(values.key, v, true).SetClass("mr-2").AsMarkdown()
+                        Link.OsmWiki(values.key, v, true).SetClass("mr-2").AsMarkdown(),
                     ) ?? ["_no preset options defined, or no values in them_"]
                     const statistics = `https://taghistory.raifer.tech/?#***/${encodeURIComponent(
-                        values.key
+                        values.key,
                     )}/`
                     const tagInfo = `https://taginfo.openstreetmap.org/keys/${values.key}#values`
                     return [
@@ -516,7 +532,7 @@ export default class LayerConfig extends WithContextLoader {
                             : `[${values.type}](../SpecialInputElements.md#${values.type})`,
                         embedded.join(" "),
                     ]
-                })
+                }),
         )
 
         let quickOverview: string[] = []
@@ -526,7 +542,7 @@ export default class LayerConfig extends WithContextLoader {
                 "this quick overview is incomplete",
                 MarkdownUtils.table(
                     ["attribute", "type", "values which are supported by this layer"],
-                    tableRows
+                    tableRows,
                 ),
             ]
         }
@@ -560,19 +576,19 @@ export default class LayerConfig extends WithContextLoader {
                 const parts = neededTags["and"]
                 tagsDescription.push(
                     "Elements must match **all** of the following expressions:",
-                    parts.map((p, i) => i + ". " + p.asHumanString(true, false, {})).join("\n")
+                    parts.map((p, i) => i + ". " + p.asHumanString(true, false, {})).join("\n"),
                 )
             } else if (neededTags["or"]) {
                 const parts = neededTags["or"]
                 tagsDescription.push(
                     "Elements must match **any** of the following expressions:",
-                    parts.map((p) => " - " + p.asHumanString(true, false, {})).join("\n")
+                    parts.map((p) => " - " + p.asHumanString(true, false, {})).join("\n"),
                 )
             } else {
                 tagsDescription.push(
                     "Elements must match the expression **" +
-                        neededTags.asHumanString(true, false, {}) +
-                        "**"
+                    neededTags.asHumanString(true, false, {}) +
+                    "**",
                 )
             }
 
diff --git a/src/Models/ThemeConfig/ThemeConfig.ts b/src/Models/ThemeConfig/ThemeConfig.ts
index 7db9787a79..5ef592c7fa 100644
--- a/src/Models/ThemeConfig/ThemeConfig.ts
+++ b/src/Models/ThemeConfig/ThemeConfig.ts
@@ -99,7 +99,7 @@ export default class ThemeConfig implements ThemeInformation {
         options?: {
             definedAtUrl?: string
             definitionRaw?: string
-        }
+        },
     ) {
         if (json === undefined) {
             throw "Cannot construct a layout config, the parameter 'json' is undefined"
@@ -130,7 +130,7 @@ export default class ThemeConfig implements ThemeInformation {
                 throw `The title of a theme should always be a translation, as it sets the corresponding languages (${context}.title). The themenID is ${
                     this.id
                 }; the offending object is ${JSON.stringify(
-                    json.title
+                    json.title,
                 )} which is a ${typeof json.title})`
             }
             if (this.language.length == 0) {
@@ -183,8 +183,9 @@ export default class ThemeConfig implements ThemeInformation {
                 new LayerConfig(
                     <LayerConfigJson>lyrJson,
                     json.id + ".layers." + lyrJson["id"],
-                    official
-                )
+                    official,
+                    <LayerConfigJson[]>json.layers,
+                ),
         )
 
         this.extraLink = new ExtraLinkConfig(
@@ -194,7 +195,7 @@ export default class ThemeConfig implements ThemeInformation {
                 newTab: true,
                 requirements: ["iframe", "no-welcome-message"],
             },
-            context + ".extraLink"
+            context + ".extraLink",
         )
 
         this.hideFromOverview = json.hideFromOverview ?? false
@@ -300,7 +301,7 @@ export default class ThemeConfig implements ThemeInformation {
                     return false
                 }
                 return o instanceof Translation
-            }
+            },
         )
 
         return { untranslated, total }
@@ -308,7 +309,7 @@ export default class ThemeConfig implements ThemeInformation {
 
     public getMatchingLayer(
         tags: Record<string, string>,
-        blacklistLayers?: Set<string>
+        blacklistLayers?: Set<string>,
     ): LayerConfig | undefined {
         if (tags === undefined) {
             return undefined
@@ -337,7 +338,7 @@ export default class ThemeConfig implements ThemeInformation {
             "Fallthrough: could not find the appropriate layer for an object with tags",
             tags,
             "within layout",
-            this
+            this,
         )
         return undefined
     }