dispose sash (microsoft#199081)

Co-authored-by: Peng Lyu <[email protected]>

Author: tisilent

src/vs/editor/contrib/find/browser/findWidget.ts

@@ -1204,7 +1204,7 @@ export class FindWidget extends Widget implements IOverlayWidget, IVerticalSashL
 		this._domNode.appendChild(this._closeBtn.domNode);
 		this._domNode.appendChild(replacePart);
 
-		this._resizeSash = new Sash(this._domNode, this, { orientation: Orientation.VERTICAL, size: 2 });
+		this._resizeSash = this._register(new Sash(this._domNode, this, { orientation: Orientation.VERTICAL, size: 2 }));
 		this._resized = false;
 		let originalWidth = FIND_WIDGET_INITIAL_WIDTH;