Refactoring: new background selector

UI/Base/FloatOver.svelte

@@ -10,7 +10,7 @@
 
 <div class="absolute top-0 right-0 w-screen h-screen p-4 md:p-6" style="background-color: #00000088">
     <div class="content normal-background">
-        <div class="rounded-xl">
+        <div class="rounded-xl h-full">
             <slot></slot>
         </div>
         <slot name="close-button">

UI/Base/IfHidden.svelte

@@ -0,0 +1,33 @@
+<script lang="ts">
+    import {UIEventSource} from "../../Logic/UIEventSource";
+    import {onDestroy} from "svelte";
+
+    /**
+     * Functions as 'If', but uses 'display:hidden' instead.
+     */
+    export let condition: UIEventSource<boolean>;
+    let _c = condition.data;
+    let hasBeenShownPositive = false
+    let hasBeenShownNegative = false
+    onDestroy(condition.addCallbackAndRun(c => {
+        /* Do _not_ abbreviate this as `.addCallback(c => _c = c)`. This is the same as writing `.addCallback(c => {return _c = c})`, 
+        which will _unregister_ the callback if `c = true`! */
+        hasBeenShownPositive = hasBeenShownPositive || c
+        hasBeenShownNegative = hasBeenShownNegative || !c
+        _c = c;
+        return false
+    }))
+
+</script>
+
+{#if hasBeenShownPositive}
+<span class={_c ? "" : "hidden"}>
+  <slot/>
+</span>
+{/if}
+
+{#if hasBeenShownNegative}
+<span class={_c ? "hidden" : ""}>
+  <slot name="else"/>
+</span>
+{/if}

UI/Base/WeblateLink.svelte

@@ -16,11 +16,11 @@
 
 {#if context}
   {#if $linkOnMobile}
-    <a href={LinkToWeblate.hrefToWeblate($language, context)} target="_blank" class="mx-1">
+    <a href={LinkToWeblate.hrefToWeblate($language, context)} target="_blank" class="mx-1 weblate-link">
       <img src="./assets/svg/translate.svg" class="w-3 h-3 rounded-full font-gray" />
     </a>
   {:else if $linkToWeblate}
-    <a href={LinkToWeblate.hrefToWeblate($language, context)} class="hidden-on-mobile mx-1" target="_blank">
+    <a href={LinkToWeblate.hrefToWeblate($language, context)} class="weblate-link hidden-on-mobile mx-1" target="_blank">
       <img src="./assets/svg/translate.svg" class="w-3 h-3 rounded-full font-gray" />
     </a>
   {/if}