I have had an issue where I have several tabs open, and they start shifting back and forth in size. Video attached: 2161.2017-09-13_11-49-27.mp4
I have seen this too. Not sure what causes it.
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alabama24: I have seen this too. Not sure what causes it.
This bug has been around since 7.0 at least!
I have seen it often, and have seen it on other people's installations as well. It seems to be related to certain combinations of numbers of tabs and panels.