I’m note sure if someone has requested something like this before, but I think that if the top menubar on DTTG (while reading PDFs) made available more color choices (re: immediate picker), the workflow of highlighting/underlining/etc could be quite faster. (see mockup below)
I, for instance, have color codes when reviewing pdf. These are:
The fast change of color in the pdf tools is, in fact, one of the reasons I keep maintaing Highlighs app, instead of just sticking to DTTG.
Note: DT3 could also benefit from something similar, but in the Mac I customised the toolbar (with BetterTouchTool) to speed up the process.