Hello,
Have no idea why, but somehow the system removes the widget from the screen at some point.
I add the widget again, but after some time I pay attention that there is nothing on the screen again.
I might think that it's a problem of the system, but I have another widgets of the Glextor App Manager, that doesn't disappear. So, looks like it relates to this particular widget.
I think, I didn't encounter with this problem at the beginning, when I started to use the widget about a year ago..
Thanks ahead