Tables seem pretty broken

What has happened to tables. They used to be really good, but they are almost unusable at the moment. They are so agonisingly slow. Moving from one cell to the next takes several seconds.

Worst of all, changing text colour in cells doesn't work at all now. If you select a range of cells and change the text colour, it just reverts straight back to black. I can highlight the text in one cell on it's own and change the colour, but that is painful for a whole table. Is there any workaround for this?