I use the virtual desktop manager Dexpot (http://www.dexpot.de/) which allows me to switch between several desktops on a Windows machine (Windows 7 Pro x64).
After installing Aptana Studio 3.5.1 (build 18.104.22.168404101117), I see an odd display behavior. If the Studio window has been hidden (that is, when I switch to another virtual desktop), when it re-displays the toolbars (below the menu but above the Editor, Project Explorer, etc. views, and on the sides) are not displayed immediately, but pop into existence after a second or two. Everything functions as expected after the toolbars appear, but it's disconcerting.
This did not happen with Aptana Studio 3.4.2, but began happening immediately when I installed Studio 3.5.1.
Right after restoring the desktop containing Aptana Studio it looks like the attached screenshot aptana_toolbar_delay_1.jpg.
After a couple of seconds it looks like the attached screenshot aptana_toolbar_delay_2.jpg.
This is with the new "Light Studio" theme. I tried some of the other themes and saw similar behavior.