All my chrome extension popups show only as small empty boxes
I had the same issue and I resolved it by:
Go to chrome://flags/
Then look for 'GPU compositing on all pages' and change the value from Default to Disabled
This solved the issue for me. This issue seems after the latest dev update to Google Chrome. This is a temporary workaround.
This happened to me in Dec 2015. I went to the chrome://flags page and clicked the "Reset all to defaults" button and that cleared this up for me.