fix window manager target element

Author: ChlodAlejandro

src/wiki/util/openWindow.ts

@@ -1,6 +1,8 @@
 import unwrapWidget from '../../util/unwrapWidget';
 import removeElement from '../../util/removeElement';
 
+export let windowManager: OO.ui.WindowManager;
+
 /**
  * Opens a temporary window. Use this for dialogs that are immediately destroyed
  * after running. Do NOT use this for re-openable dialogs, such as the main ANTE
@@ -11,15 +13,22 @@ import removeElement from '../../util/removeElement';
  */
 export default async function openWindow( window: OO.ui.Window ): Promise<void> {
 	return new Promise( ( res ) => {
-		let wm = new OO.ui.WindowManager();
-		document.getElementsByTagName( 'body' )[ 0 ].appendChild( unwrapWidget( wm ) );
-		wm.addWindows( [ window ] );
-		wm.openWindow( window );
-		wm.on( 'closing', ( win, closed ) => {
+		if ( !windowManager ) {
+			windowManager = new OO.ui.WindowManager();
+			const parent = document.getElementById( 'mw-teleport-target' ) ??
+				document.getElementsByTagName( 'body' )[ 0 ];
+
+			parent.appendChild(
+				unwrapWidget( windowManager )
+			);
+		}
+		windowManager.addWindows( [ window ] );
+		windowManager.openWindow( window );
+		windowManager.on( 'closing', ( win, closed ) => {
 			closed.then( () => {
-				if ( wm ) {
-					const _wm = wm;
-					wm = null;
+				if ( windowManager ) {
+					const _wm = windowManager;
+					windowManager = null;
 					removeElement( unwrapWidget( _wm ) );
 					_wm.destroy();
 					res();