Fix UI glitch with webkit hi-res rendering for #482

These changes should fix material circle is not properly rendering when shown in chrome in high resolution machines - MBP Retina.
Merge pull request #510 from varchev/fix_ui_issue_with_webkit_retina

Fix UI glitch with webkit hi-res rendering for #482
#130 - UI fixes

1. Highlighting fields with errors
2. Poll for changes checkbox position

This also fixes issue #511 and #513