The recent emergence of this issue, sometimes open two projects, a filtration column, without the filter bar; sometimes do not filter bar. Solution is as follows:
1, frame to try to move the log vertically and horizontally (best)
2, try to enable and disable Split Mode (sometimes effective)
3, try to enable and disable Windowed Mode (it seems more reliable)
4, try to restart Studio (low probability repaired)
5, try to restart the computer (sometimes effective)