Wicket 6.x IE9 inmethod-grid hover fix Issue #44

This is the fix for the Issue #44 for IE9. After some future tests I found some additional places which can trigger this buggy behavior and also included a fix for those.

This is a fix only for script-jq.js as I only use the JQuery version of the inmethodgrid.  

Is the YUI version still fully supported? Or should it just be dropped in a future release? 

As script-jq.js is the same in master as in the wicket-6.x branch, I can create a pull request which would update the script in master. But I can not test this script with the master branch, as my project is still wicket-6.x.