Bug 445192 - RAP: Tooltip for label of disabled FormFields not displayed
https://bugs.eclipse.org/bugs/show_bug.cgi?id=445192

Fixed the issue that no tooltip is shown on the label of disabled form
fields.

See bugzilla for SWT:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=383073

Change-Id: I4aa7b6a877f0fff3f7139f110dda2bb3bb90b525
Reviewed-on: https://git.eclipse.org/r/37067
Tested-by: Hudson CI
Reviewed-by: Claudio Guglielmo <claudio.guglielmo@bsiag.com>