JS error if inputting invalid issue key into Quick Search

if you enter an invalid issue key (e.g. 98765) into the Quick Search, you get an error in I.E.:
Line: 40
Char: 7
Error: 'Calendar._TT.WEEKEND' is null or not an object
Code:0
URL: http://jira.atlassian.com/browse/JRA-98765
This didn't happen on previous versions. I tested on 3.3.3 and it didn't do tjhat.