I've been working on a project for a year that has worked fine. I upgraded to 4.5.1 and now can no longer edit several of my components that were localized. I solely get a red X and a design error that says "Assets failed to compile. Design Mode is unable to display the document styles, skins, and images because the following assets have failed to compile:Details :unable to open 'locale/en_US'(command line - Line:-1)"
I've a folder with locale/en_US and it actually localizes fine if I run the app, but I can not longer edit in design mode which, as you might guess, really puts a damper on moving objects by pixels.