Fix crash when dragging element from more palette to parent

Author: mathesoncalum

src/palette/qml/MuseScore/Palette/internal/PaletteTree.qml

@@ -264,6 +264,8 @@ StyledListView {
         property var control: null
         property var popupModel: null
 
+        readonly property bool isPopupOpen: morePopup.active && morePopup.item.isOpened
+
         sourceComponent: MoreElementsPopup {
             maxHeight: Math.min(0.75 * paletteTree.height, 500)
 
@@ -298,7 +300,6 @@ StyledListView {
 
             onClosed: {
                 enablePaletteAnimations = false;
-                morePopup.active = false;
             }
 
             function scrollToPopupBottom() {
@@ -327,17 +328,20 @@ StyledListView {
         }
 
         function close() {
-            if (morePopup.active) {
+            if (morePopup.isPopupOpen) {
                 morePopup.item.close()
             }
         }
 
         function toggleOpened(model, control, parent) {
-            if (morePopup.active) {
+            if (morePopup.isPopupOpen) {
                 morePopup.close()
                 return
             }
 
+            // Force a full re-load of the component (ensures the geometry updates, etc.)
+            morePopup.active = false
+
             morePopup.parent = parent
             morePopup.popupModel = model
             morePopup.control = control
@@ -385,7 +389,7 @@ StyledListView {
             }
 
             Component.onDestruction: {
-                if (morePopup.active && morePopup.popupModel === model) {
+                if (morePopup.isPopupOpen && morePopup.popupModel === model) {
                     morePopup.close()
                 }
             }
@@ -472,7 +476,7 @@ StyledListView {
 
             highlighted: (activeFocus && !selected) || DelegateModel.isUnresolved
 
-            property bool popupExpanded: morePopup.active
+            property bool popupExpanded: morePopup.isPopupOpen
             onPopupExpandedChanged: {
                 paletteTree.interactive = !popupExpanded
             }