Hello, In your case, try this approach: procedure TMainForm.UniFormScreenResize(Sender: TObject; AWidth, AHeight: Integer); begin if AWidth < 800 then begin YourContainerPanel.JSInterface.JSCall('getLayout().setVertical', [True]); //vbox YourContainerPanel.JSInterface.JSCallDefer('updateLayout', [], 20); end else begin YourContainerPanel.JSInterface.JSCall('getLayout().setVertical', [False]); //hbox YourContainerPanel.JSInterface.JSCallDefer('updateLayout',