Design Mode Problems Flash Builder 4.5.1

If you have tried to switch to Design Mode in Adobe Flash Builder 4.5.1 and see nothing but white, look at your Design Mode Problems tab: Window > Show View > Other > Flash Builder folder > Design Mode Problems.

If you see this message:

SWC file failed to load. Any component dependent on this SWC file will not be displayed in the Design Mode.

The SWC may have failed to load because of:

*  Incompatible definitions caused by usage of a different SDK version

*  Missing referred class definitions

Switching my SDK from 4.5.1 to 4.5 was a suitable workaround. In my case, my custom mobile skins library depends on sdks4.5.0frameworksthemesMobilemobile.swc which didn’t want to play nice with 4.5.1 apparently.