I just want to post something strange. Dunno if you want to "fix" this, I just post this:
I transfer a large amount of data (almost my whole HDD^^) to my server in my LAN. At the same time I tried to compress a DVD-ISO with 7-Zip, just to find out, how strong it copuld be compressed. Point is, my Intel i5 CPU was 100% busy and 7-Zip used 7 GB of my 8 GB RAM. Unfortunately, I had to kill explorer.exe, because I could not browse through my directories an more to drag more content to WinSCP.
After a while, 7-Zip has finished and my computer was responsible again. But The GUI of WinSCP looks very strange. Even the context-menu that appears when right-clicking on the transfer-queue. See the screenshot that I attached.
However, the transfer goes on fine, it's just the GUI that is concerned.
Using WinSCP 5.0.7 Build 2268 under Windows 7 64-Bit with Intel i5 (4x 3.4 GHz) and 8 GB RAM.