I can see from the launcher that the Update Manager is running - it has the little triangle by it. However, I am having trouble seeing the window. If I click on it from one desktop, it switches to another, so I assume that the Update Manager has its window on that other desktop, but it still doesn't show anything.

If I click alt-tab to switch between apps, I can see that the Update Manager is there, but selecting it just shows me a blank screen. Also, when I select it, while still holding the alt-key, I see the top menu bar switch to 'Update Manager', but when I release alt, it changes back to Ubuntu Desktop.

It's almost like the app is off the screen somewhere, perhaps with just a single pixel showing or something like that.

disclaimer: One thing that might be affecting things is that I have 'focus follows mouse' configured, which makes things a bit funky with the menu not being on the window, where it should be (perhaps there's a way to put it back with the window?) - I like to be able to type into background windows, and manually control which window is in the foreground.