title: IntelliJ GUI designer missing mnemonic
body: <p>I've just migrated from Eclipse to JetBrains IntelliJ IDEA and I find it very annoying when it comes to using designer. When I create a new GUI form the designer works fine for some time. Then suddenly after switching to other class or after closing and reopening IntelliJ it shows me XML code only and I have no option to switch to designer mode. This time I have form with three buttons and IntelliJ shows me XML with three notifications at the top "missing mnemonic: name_of_a_button" despite that I didn't use any and never wanted to. By the way even if it works fine I don't have that switch at the bottom to toggle between designer and text mode. Why is that?</p>