Weird meeting request in Thunderbird

Hi All. I have used Meeting Requests in T-bird for some time but recently I have had trouble with the Invitees dialogue. It used to be wholly contained within around 50% of a screen width, but now it spreads across three screens which is an irritation as I use only one screen. The info I need to enter is on the very far left and the OK Button is on the far right. Here is the link to my screenshots: https://drive.google.com/drive/folders/1MzJN0cBMY8r2Tx-Xzf9cFY-FM-99m27s?us… I have written to Mozilla to get a solution, but have had no reply. Perhaps there is an easy solution to this. Any help would be appreciated. Many thanks Andrew Greig