I would like to request a keyboard shortcut for jumping to the "next untranslated (empty target) segment." This is useful especially when I go back and forth within the project for one reason or another.
good suggestion, I miss it, too.
Your screenshot seems to be showing the grid during the QA. Here, CafeTran highlights the 100% matches in grey as well. This marking is probably slightly confusing and may be removed in the future.
The option (menu) Action > Skip > Translated segments will be present in the next update.