**System Information**
OSX 10.10.3 but I guess irrelevant
**Blender Version**
Broken: 2.74.2 (3bb7e14)
Also checked RC2 and shows same 'bug'
in Video Sequence Editor preview screen, with view settings on Proxy size anything smaller than 100%
the preview scales down as soon as 'Show Overexposed' value > 0
**Exact steps for others to reproduce the error**
Start new file,
goto Video Editing Screen Layout,
open an image or movie so it shows something in the preview window
open properties with N if not visible
Set Proxy Render size to 25% (as an example)
increase 'Show Overexposed' ( > 0)
observe scaling of preview..
thanks for looking into it..
Best Regards,
Roel
IRC: kostex