diff --git a/UI/OpeningHours/OpeningHours.ts b/UI/OpeningHours/OpeningHours.ts
index 51a7d697b4..a37e831d8e 100644
--- a/UI/OpeningHours/OpeningHours.ts
+++ b/UI/OpeningHours/OpeningHours.ts
@@ -316,12 +316,21 @@ export class OH {
         }
     }
 
+    /**
+     * 
+     * OH.ParsePHRule("PH Off") // => {mode: "off"}
+     * OH.ParsePHRule("PH OPEN") // => {mode: "open"}
+     * OH.ParsePHRule("PH 10:00-12:00") // => {mode: " ", start: "10:00", end: "12:00"}
+     * OH.ParsePHRule(undefined) // => null
+     * OH.ParsePHRule(null) // => null
+     * OH.ParsePHRule("some random string") // => null
+     */
     public static ParsePHRule(str: string): {
         mode: string,
         start?: string,
         end?: string
     } {
-        if (str === undefined) {
+        if (str === undefined || str === null) {
             return null
         }
         str = str.trim();
@@ -330,13 +339,13 @@ export class OH {
         }
 
         str = str.trim();
-        if (str === "PH off") {
+        if (str.toLowerCase() === "ph off") {
             return {
                 mode: "off"
             }
         }
 
-        if (str === "PH open") {
+        if (str.toLowerCase() === "ph open") {
             return {
                 mode: "open"
             }
diff --git a/UI/OpeningHours/PublicHolidayInput.ts b/UI/OpeningHours/PublicHolidayInput.ts
index 6e4e621e8f..05274552bf 100644
--- a/UI/OpeningHours/PublicHolidayInput.ts
+++ b/UI/OpeningHours/PublicHolidayInput.ts
@@ -26,6 +26,20 @@ export default class PublicHolidayInput extends InputElement<string> {
         return true;
     }
 
+    /**
+     *
+     * // should construct an element
+     * const html = new PublicHolidayInput().InnerConstructElement()
+     * html !== undefined // => true
+     * 
+     * // should construct an element despite having an invalid input
+     * const html = new PublicHolidayInput(new UIEventSource("invalid")).InnerConstructElement()
+     * html !== undefined // => true
+     * 
+     * // should construct an element despite having null as input
+     * const html = new PublicHolidayInput(new UIEventSource(null)).InnerConstructElement()
+     * html !== undefined // => true
+     */
     protected InnerConstructElement(): HTMLElement {
         const dropdown = new DropDown(
             Translations.t.general.opening_hours.open_during_ph.Clone(),
@@ -75,6 +89,9 @@ export default class PublicHolidayInput extends InputElement<string> {
         const value = this._value;
         value.map(ph => OH.ParsePHRule(ph))
             .addCallbackAndRunD(parsed => {
+                if(parsed === null){
+                    return
+                }
                 mode.setData(parsed.mode)
                 startTime.setData(parsed.start)
                 endTime.setData(parsed.end)