I found a thread on Google on the subject of 'white glow' on the task bar.
To fix it I done the following:
Right click on desktop Click on 'Personalise' Click on 'Window Colour' icon at the bottom Uncheck 'Enable Transparency' Click on 'Save' and close.
Repeat the above but 'Check' the 'Enable Transparency' box and the 'Save' and close.
The task bar is now back to normal without that horrible white glow.
It worked for me.