User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0 Build ID: 20160502172042 Steps to reproduce: 1. Set default font size to Small: Tools > Options > Composition > General > HTML > Size: Small 2. Set Signature: Tools > Account Settings > Some account > Signature text > Use HTML: Yes, Signature: Some signature plain text 3. Open new message: File > New > Message 4. Click on first line (above signature text) and type some text -> font size is small (this is OK) 5. Open another new message: File > New > Message 6. Click on signature text 7. Click on first line (above signature text) and type some text -> font size is medium (this is wrong) Actual results: - clicking on signature text resets default small font size to medium - signature text has invalid font size (it is medium instead of default composing font size – small) Expected results: - clicking on signature text retains default small font size - signature text has valid font size (default composing font size – small)

You need to understand the font size mechanism. When you create a new message, the font and font size are set from your preferences. When you type, you get what you want. When you click elsewhere instead of typing, the font and size are picked up from where you click, most likely medium when you click into the signature. If you then click back at the beginning, you lost the initial settings. Type something before clicking into the signature and you'll be right. Given our resources and the fact that editing the content of the mail body is actually controlled by Mozilla core software, there isn't a chance that this bug will be fixed in the foreseeable future. Sorry.

(In reply to Jorg K (PTO during summer, NI me) from comment #1) > You need to understand the font size mechanism. > > When you create a new message, the font and font size are set from your > preferences. When you type, you get what you want. When you click elsewhere > instead of typing, the font and size are picked up from where you click, > most likely medium when you click into the signature. I know it, but my signature has no explicitly specified font. It is pure text and in context of default message font it should have same font as other message text. In addition, if default size is small and I specify font for signature, for example <font size="-1"> (small), clicking on the signature despite it resets font to medium. > > If you then click back at the beginning, you lost the initial settings. Type > something before clicking into the signature and you'll be right. > > Given our resources and the fact that editing the content of the mail body > is actually controlled by Mozilla core software, there isn't a chance that > this bug will be fixed in the foreseeable future. Sorry.

Font size and style have changed while I am typing, without clicking anything. I have been just happily typing along, and abruptly the size and style of the font have changed simultaneously. And then, after a while, it may spontaneously return to the original font. If this is controled by Mozilla core software, I wonder if my program has been corrupted. If so, might removing and reloading the Thunderbird program fix it? Although this doesn't happen frequently, just occasionaly. Could a corruption produce this problem inconsistently? In reply to Jorg K (GMT+1) from comment #1) > You need to understand the font size mechanism. > > When you create a new message, the font and font size are set from your > preferences. When you type, you get what you want. When you click elsewhere > instead of typing, the font and size are picked up from where you click, > most likely medium when you click into the signature. > > If you then click back at the beginning, you lost the initial settings. Type > something before clicking into the signature and you'll be right. > > Given our resources and the fact that editing the content of the mail body > is actually controlled by Mozilla core software, there isn't a chance that > this bug will be fixed in the foreseeable future. Sorry.