I find myself pressing the sync “cloud” symbol several times because I am never sure whether sync has started or has finished. (Similar, in the desktop version I keep clicking on the sync symbol when there is a blue dot but since there is no visual feedback that sync is on, one tends to click several times. The source are probably the few extra (milli)seconds from the sync to Dropbox but nevertheless, visual feedback on the process in the main window would be good (not sure when the other extra window comes up and when not).
The activity window shows specific Sync activity and can be shown as much as you’d like. 
What would you like to suggest could be better here?