Current wmf version: 1.33.0-wmf.8 (2859494) 2018-12-12T19:34:02
I had the following setting in my https://en.wikisource.org/wiki/User:Ineuw/common.css which set the height of the Textbox1 area at 280 pixels. Lately, this window measures 475-500 pixels high, which covers the display space of the OCR text display, which in turn prevents me from editing the last paragraphs of the text. The setting no longer affects Textbox1, and the handle in the lower right corner of the frame used for resizing is also frozen/locked.
This happens only in Firefox 63+. I checked Chrome & Vivaldi and the Textbox1 height is correct.
textarea#wpTextbox1 {
font-size:1.1rem !important; line-height:1.0 !important; color:black !important; background-color:#DCDCDC !important; height: 280px !important; //<------------------------
}