UI glitches when window is being resized.

[larz0]

To reproduce:

1. Rename extensions folder to isolate the issue
2. Expand Brackets /src folder
3. Resize the window

Actual result:

• Text glitches in the project panel
• Layout is slightly laggy on edges

Expected result:

• See Reflow CC (:pray: @anirudhsasikumar)

[njx]

Is this a dupe of #4128? If so, maybe close that one out since this one has slightly more detail.

[larz0]

Last time I was able to fix it by removing extensions. This time I also noticed the flashing of file tree.

[gruehle]

I copied the steps to repro into #4128. Closing this as a dupe.