[Pharo-dev] Fix for 21809

Hi, More freedom in the text color for tooltips for a better visibility  (see screenshot). https://pharo.fogbugz.com/f/cases/21809/Both-tooltips-text-and-background-co... Change set fix attached to the bug ticket. I don't learn yet the current procedure to integrate fixes so I let it for someone with the know how. Hilaire -- Dr. Geo http://drgeo.eu