By saying "upgraded" in my previous post I have meant uninstalled 268/ installed 276. Is the download link you point it has a higher version then 276 ? if yes then I can try. Used a tool called AppCleaner, if you think the uninstall was made not clean or wrong(which I don't think), then suggest pls how to make a clean unistall of the designer.
just wanted to let you know that it happens more with chrome, if designer is hidden and chrome is shown and get's the focus for a while, after which designer get's the focus back, for sure is dead, it's about last build(298) too.
Yes we've been able to reproduce it. However only with packaged version of Designer which makes this hard to get to the bottom of. I've heard that in some cases you can resize the window and it jumps back to life.
Here one more: when designer is in coding mode it doesn't freeze.
Also noticed that when there's a project with many views, and after working a while with it, then trying to switch between views is kind annoying because it doesn't, or if switches then the view is mixed with the previous and the layout is broken, thus there's something with the preview module.
Will post later some pictures for clarity, hopes it helps.