[Geary] Bug? Underline only toggles

[johnywhy gmail com]

hi, i can't find this in the tracker (but not sure what to search for). 

1. send a message containing a partially underlined paragraph
2. reply to your own sent message
3. copy the partially underlined paragraph from the quoted message into the new message
4. (the previous might not be relevant. Here's where the visible problem begins)
5. try to remove underlining by:
6. drag down from the beginning of the paragraph
7. click underline button. The whole paragraph gets underlined. 
8. click  underline button again. The paragraph returns to partially underlined state. 

• Expected: All underline should be removed at this point. 

This problem goes away if i drag across instead of down. Ie, if i don't include the paragraph break in the selection. 

i can't duplicate the issue, so here's a screencast:

https://youtu.be/YMluHyKa4Oc