Hi Kirk, Having tried this I can tell you it doesn't have an effect on my problem I'm afraid.
In the meantime, I've found something else causing me a headache....
With a folder of images displayed in a contact sheet, if I have several images within that sheet defined by a colour class (ie red or green) I can no longer quickly 'flick' between the whole folder and the colour tagged images by selecting the button furthest to the right in the screengrab.
In PM 5 hitting that button would instantly show the images tagged by colour class and then with another press show me the whole folder, the behaviour in PM6 causes the amount of colour tagged images to slowly build in the background... ie when pressing the far right button the amount of colour classed images changes incrementally with every press.