I am using Apex 5.1.1 and I have a screen that utilizes a RDS, but I have also added another region that utilizes a tab container and has 3 tabs. I have found that when I click one of the tabs the screen will move down and if enough data the tab will not be seen anymore. I then went to the Universal Theme Application(tabs and region display selector section) to see how the tabs worked there(on apex.oracle.com). I see the same issue.
I am curious if anyone else has come across this problem?
Did you search to find out?
This is due to bug 25851580. A potential workaround is available: Error when creating a Tab Subregion Tabs in online Oracle APex
Apparently I did not search enough. I should have put the error in my search. I do appreciate you letting me know.