I was in the process of searching my files to attach one to an email when the attachment window suddenly expanded from approx 50% of the screen to almost full screen and I can find no way to reset it. I can see the sideand bottom edges of the window, and move the expand/contract arrow on the cursor to these sides and the bottom corners, but it does not operate, and there is no button to minimise or adjust it. I have just checked and it is operating perfectly fine on both Firefox and the main Thunderbird window, and email viewing windows. Is this a change to the program settings - it appears to only apply to the "Attach" setting - viewing attachments and emails are as they always were.