I'm trying out GTG for the first time, after learning about it in a lucid lynx review. I went through the tutorial, dutifully completing the tutorial tasks as I went through them (cool tutorial btw. neat how it's integrated into the application). I tried out the RTM plugin, then realized I didn't need all my random personal "sometime" todo tasks synced on my work laptop, since they were showing up in the task panel applet. So I removed the RTM plugin. Sometime around then, I found that closing the main window didn't work. And when the close button was clicked, then closed-task in the tutorial (the plugins one), appeared in a window with appropriate title but grayed out contents. The Main Window remains open and I am unable to close it, though minimizing works.
Note that the I deleted the Learn how to use Plugins task while having this problem, but it continues to appear when attempting to close the main window. It seems to happen every other time I click the (x).