I have a tab control that has stopped working at run time. It is acting like it is disabled when it is Enabled. At edit time I am able to click on the tabs and they visually change. When I run, clicking on the tabs does not change tabs. I have reduced the vi to a simple loop with 200 mS delay and the tab, with nothing else. The tab controls is the only thing in the vi. I have ensured that the tab is Enabled in Properties dialog box. I did notice one odd thing: the Key Navigation tab (in Properties), it is all greyed out. Again, the tab control in in fact Enabled but it is behaving like it is not. I have tried recompiling. Is there some other setting? Why is key naviation greyed out? I am using LabVIEW 2015. Thanks!