If the caret overlaps part of the character that it is not positioned on, then it will often erase part of that character (depending on where it was in the blink cycle). 1. Load the attached testcase font-change.html 2. Toggle on caret browsing with F7 (you can turn it off with the same key) 3. Click in the text and arrow to "g" and then arrow somewhere else Half the time a piece of "f" will be erased.
A related problem leaves huge chunks of characters on the screen. 1. Go to http://www.mozilla.org/editor/midasdemo/ 2. In the editor, select font size 7 3. Type "ffffffffffff" and then start backspacing. A very large "turd" will be left from some of the f's
I'm able to reproduce the problem in comment 1 in both Firefox 2 and Thunderbird 2. Therefore that part is likely a duplicate of some other bug. However, the caret problem is new -- perhaps due to the fact that the caret is drawn as a solid block now?
This depends on the bug about giving text frames overflow (and about reporting such overflow from the font code), which I think roc has been working on recently; I suspect it's a duplicate of some of that bug's existing dependencies.
In current nightly I can still reproduce it but only selecting Courier + Italic Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20081007 Minefield/3.1b1pre
(In reply to comment #4) > In current nightly I can still reproduce it but only selecting > Courier + Italic still reproduces per above with Mozilla/5.0 (Windows; Windows NT 6.0; rv:2.0b3pre) Gecko/20100724 Minefield/4.0b3pre (.NET CLR 3.5.30729)
Tested in latest Release and Nightly and could not reproduce the errors Version 46.0.1 Build ID 20160502172042 Version 49.0a1 Build ID 20160519030232 I will close as Resolved-WFM