Mobile: Fixes #13151: Reset the state of undo and redo buttons when switching editor (#13505)

packages/app-mobile/components/screens/Note/Note.tsx

@@ -660,6 +660,17 @@ class NoteScreenComponent extends BaseScreenComponent<ComponentProps, State> imp
 			});
 		}
 
+		// Reset undo/redo button state when switching to edit mode or when switching between markdown and rich text editors, since the editor is
+		// recreated and loses its undo/redo history
+		if (this.state.mode === 'edit' && (prevState.mode !== this.state.mode || prevProps.editorType !== this.props.editorType)) {
+			this.setState({
+				undoRedoButtonState: {
+					canUndo: false,
+					canRedo: false,
+				},
+			});
+		}
+
 		if (prevProps.noteId && this.props.noteId && prevProps.noteId !== this.props.noteId) {
 			// Easier to just go back, then go to the note since
 			// the Note screen doesn't handle reloading a different note