452283: Performance issue on editable table 

Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=452283
443508: Cell & Row tooltips in SWT tables do not work correctly 
Partial fix for Issue 1,2,3

Change-Id: I8847e962d5830abd51500ebaa864b3e00d896643
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=443508