Showing after hiding window removes all content - user-interface

Question

I am using following code which produces a main window with a button to open other window. I want to be able to repeatedly hide and show other window. Closing main window should exit the program:
package main
import ("github.com/andlabs/ui")
func main() {
ui.Main(makeAllWins)
}
var mainWindow *ui.Window
var otherWindow *ui.Window
func makeAllWins(){
makeMainWin()
makeOtherWin()
mainWindow.Show()
}
func makeMainWin(){
var otherButton = ui.NewButton("Other module")
otherButton.OnClicked( func (*ui.Button) { otherWindow.Show() })
var box = ui.NewVerticalBox()
box.Append(ui.NewLabel("Select module"), false)
box.Append(otherButton, false)
mainWindow = ui.NewWindow("Hello", 200, 100, false)
mainWindow.SetChild(box)
mainWindow.OnClosing( func (*ui.Window) bool { ui.Quit(); return true } )
}
func makeOtherWin(){
var box = ui.NewVerticalBox()
box.Append(ui.NewLabel("label1"), false)
box.Append(ui.NewLabel("label2"), false)
box.Append(ui.NewLabel("label3"), false)
otherWindow = ui.NewWindow("Other", 200, 100, false)
otherWindow.SetChild(box)
otherWindow.OnClosing( func (*ui.Window) bool { otherWindow.Hide(); return true } ) // I THINK PROBLEM IS IN THIS LINE
}
However, when I show the other window after hiding it once, all the labels are gone. On repeating, the program crashes with following error:
fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0x67fb0a pc=0x67fb0a]
Where is the problem and how can it be solved. Thanks for your help.

Answer 1

Here:
otherWindow.OnClosing( func (*ui.Window) bool { otherWindow.Hide(); return true } )
you should be returning false instead of true. As it is, the window is getting destroyed when you close it, leading to the segmentation fault when you try to reference it later.
Per the documentation comments:
OnClosing registers f to be run when the user clicks the Window's
close button. Only one function can be registered at a time. If f
returns true, the window is destroyed with the Destroy method. If f
returns false, or if OnClosing is never called, the window is not
destroyed and is kept visible.