After running some more tests, it just seems that AdvMessageDialog needs some real testing when using Content Regions, especially when using then with the 'Allow' option of the async click.
Sorry to keep adding to this but I'm discovering more things. If the Content Region has an invisible IWDatePicker on it with RenderInvisibleControls = true on the region then the region does not disappear....
The update will be available with the next release of the TMS IW Component Pack
We are aware that there can be issues when using a ContentRegion and async events in IE.
Unfortunately this is a complex problem that is related to IntraWeb interaction with the IE browser due to the way the IWRegion is placed in the IWAdvMessageDialog control.
As a workaround you could try using synchronous events instead of asynchronous events.
But the 'allow' doesn't seem to work for sync events. i.e. the dialog just closes no matter which button is pressed or if allow := false is used...
Generally, with limited use, the async stuff works (if that above fix is applied)... can you share that as something I can temporarily add?
Just a follow up... it appears that the issue with a AdvMessageDlg content region disappearing when an ASYNC event occurs (timer for example) is still only resolved by putting a TIWDatePicker on the form. (Other controls may also 'fix' the problem but I just drop one of these on the region, hide it, make the region RenderInvisibleControls). I believe I reported this a while ago but if you need an example, please let me know.