I noticed that for a long time now.
Always where thinking i mabye not click right.
But it really the import window close button.
The problem is that when i try to cose the import dialog by pressing the [X] It does not respond. It need sometimes a few clicks.
I just needed to click 10 times on the [X]. It looks like the click area sansar is checking is very small or at least not correct.
Add, i just did noticed the same problem with the properties close button. I tried the inventory window to, same problem.
And because the buttons are very small, it amplify the problem. 2 pixels wrong with your mouse pointer and it fail to respond.
This seems to happen especially around the top left at the first pixel of the X