Removing Elements in a StackPanel - google-apps-script

Question

All,
I am trying to implement a StackPanel containing multiple sub-panels to collect user data. Each subpanel (I have named them SwapRecordPanels) represents a line in a Google spreadsheet containing the data for two people who want to swap which days they will work. The SwapRecordPanels contain a delete button. On clicking the delete button, I would like the SwapRecordPanel to remove itself from the StackPanel.
However, I have found that when I attempt to remove an element from a StackPanel, the change does not register in the GUI. As an attempt at the proof of the concept that I could delete elements in a StackPanel, I added an extra button titled "Click Me". As you can see in the code below, its handler attempts to remove an element from the StackPanel "LeftPanel." However, when I click the button, the "LeftPanel" remains unchanged. I'm wondering if there's some sort of refresh/repaint method to be called to update the GUI. If not, could anyone offer any advice? Any help would be greatly appreciated.
function myViewer() {
var myapp = doGet();
SpreadsheetApp.getActive().show(myapp)
}
function doGet() {
var myapp = UiApp.createApplication();
var LeftPanel = myapp.createStackPanel().setId("LeftPanel");
var LeftScrollPanel = myapp.createScrollPanel(LeftPanel).setPixelSize(410,200)
myapp.add(LeftScrollPanel)
var SwapPane1 = SwapRecordPanel(LeftPanel);
var SwapPane2 = SwapRecordPanel(LeftPanel);
LeftPanel.add(SwapPane1,"Test 1 Header");
LeftPanel.add(SwapPane2, "Test 2 Header");
var myButton = myapp.createButton("Click Me").addClickHandler(myapp.createServerHandler("ButtonClicker"));
myapp.add(myButton);
return myapp;
}
function ButtonClicker()
{
Logger.log("I was clicked")
var myapp = UiApp.getActiveApplication();
var LeftPanel = myapp.getElementById("LeftPanel");
LeftPanel.remove(myapp.getElementById("panel1"));
}

Answer 1

You have to "return" the changes to the app from the handler function for the UI to update.
Simply add return myapp; at the end of the ButtonClicker() function.