On a contentpage I have a Ultrawebtab with a Webdropdown on the third tab. If I load the form with the third tab set as the start tab and load the form, the webdropdown works fine but if I load the form with the first tab as the start tab, the webdropdown does not drop down.
This behavior was reported to us in a support case recently.
In debugging this, we were able to reproduce this by putting the WebDropDown control in a DIV element, hiding that DIV in the desitgner using CSS, and unhiding the DIV in JavaScript in response to a button click. This is similar to the functionality that WebTab uses for showing tabs (at least when you're not using TargetURLs), and the behavior we saw was the same.
We've reported this to our developers for further research, as development issue number 24832.
I'm going to pass your information to a Developer Support Engineer to create a case on your behalf. That way, you'll be notified whenever a solution is availalbe to development issue 24832.
For the benefit of others on this thread: If you encounter similar behavior and would like to be notified of a fix, please submit a support request and include a link to this forum thread.
There was one other piece of information I meant to include before I posted my previuos message.
As a workaround when using WebTab, you can set the AutoPostBack property of the WebTab control to true. This will cause a postback to be generated whenever you switch tabs. This will allow the WebDropDown on any tab to function properly.