JS: Persistent Modeless Dialog

Question

I am trying to make a modeless dialog box for InDesign, but for some reason the dialog always closes after the script runs (i.e. I see the dialog for a brief second until the script finishes running, then it's gone). I cannot get it to persist. I need to be able to edit a document while the dialog is open. Any suggestions?
I am using the ScriptUI classes to create a dialog with the property 'palette'.

Answer 1

I tried that, still the same. I can put that at the beginning of the script, right? Along with my application target?
Example:
#target InDesign
#targetengine "session"
Here is my whole script (don't laugh too hard, I am still trying to figure this out ):
#target InDesign
#targetengine "session"
function closeWindow(){
     posWin.close();
var posWin = new Window(
     'palette',
     'Position the Image',
     undefined, {
          resizable: false,
          closeButton: true,
          maximizeButton: false,
          minimizeButton: false,
          independent: false,
          borderless: true
posWin.location = [0, 0];
posWin.info = posWin.add('panel', undefined, undefined);
posWin.action = posWin.add('panel', undefined, undefined);
posWin.action.orientation = 'row';
posWin.action.prevMaterialBtn = posWin.action.add('button', undefined, '<-- Previous Material');
posWin.action.cancelBtn = posWin.action.add('button', undefined, 'Cancel');
posWin.action.cancelBtn.onClick = closeWindow;
posWin.action.nextMaterialBtn = posWin.action.add('button', undefined, 'Next Material -->');
// This function will call an instance of a template, delete the link to the current photo, replace it with a new photo and then wait for an onClick (or some other) event.
// It will then write the information to the XMP, close the template and open the next template.
posWin.show();