Changing the title of the series slightly so as not to confuse Googlers who think that I might actually get a working extender out of this. So to clarify, I'm trying to build an extender and reporting back on my trials and tribulations.
So on the advice of Ted Glaza, I tried creating my own Sys.UI.Control within my code. I added the following line to the initialize call for my extender:
_collapsePanel = new Sys.UI.Control( _collapsePanelID );
There's more. When I try to leave the page, I also get the following:
No idea what to make of that. As you probably suspect, there is no mention of displayMode in any of my code. So how do I track this down? And if I do track this down and it's in Atlas code where I think it is, what do I do about it?
To be clear, I know the bug is in my code, not in the Atlas code. What I mean by that last question is: If I can even find which line is causing the error, what do I do to fix it?
Stay tuned, kiddies!