If you are working in a form that has Tabable objects and select an item that opens a list in a new window and then close it, the form may no longer accept tab keystrokes. It may seem that the form is still Tabable because a field still has focus; however, when you hit the tab key nothing happens. If this is happening to you, check to see if you are using a floating palette window. You will notice that if you close the floating palette window before opening and closing the list window, the form will still accept tab keystrokes. This is because the floating palette has become the frontmost process. Therefore, the form will not recognize the tab key unless you click onto the form again. To get around this problem, use the Hide Process command on your floating palette before opening a new window. This will make sure that when you close the window and return to the form, the form will again be the frontmost process.
Here is an example object method that opens a window in front of a form, with a floating palette window already running in the process ID '<>ToolPaletteID':
$vWinRef:=Open window (100; 100; 200; 400; Movable dialog box ; "Listing")