Make download panel dropdown button unselectable

Avoid ugly selection colors when people double-click the dropdown
button.
(Why would people double-click the dropdown button? Not sure, but
I did, so...)

Change-Id: If505c7b62ca501a492aa7f85d2f6c92790ecd6dd
Remove the gap the between the download button and the dropdown menu

Change-Id: I640c5e759880f4a1fcbe213d793380ad9caca23c
Merge "Make download panel dropdown button unselectable"
Merge "Remove the gap the between the download button and the dropdown menu"