Windows 8.1. Mozilla 68.10.0 (32-bit) I run a filter that moves incoming emails to different folders. When I open any email from any sender from one particular folder, it always opens with the bottom of the message pane extending off the bottom of the screen. This occurs no matter how i resize the message pane. Close it, open it, and it's back to the same size extending below the bottom of the screen. Now, when I go to resize these message panes, and click with the cursor (↕) straddling the very top outside border of the pane like i'm going to pull the top border down, the top border immediately jumps down the screen about 3/4 of the way as soon as i start to pull it down. I have to then go down and click on this border line again, drag the top down farther, then click inside the upper border in the very top box of the message pane, and drag the whole pane up the screen until i can see the bottom of the message pane. Same opening size and position on the screen every message from this folder. Have to go through this every time because most of the time it's the attachment i'm interested in. Tried maximizing the pane instead of manually resizing it, but once closed, messages in this folder will always open up to that same size, in the same part of the screen, with the bottom off-screen. Getting a feeling there's something deep that's wrong because of the way the pane always initially jumps down and resizes as soon as i click on the border. Like Mozilla doesn't know how big the pane is.