Pretty much as the subject says.
I was updating my Bullrun map for 0.9. I turned on the grid and suddenly my CPU use jumped to 50% (100% of 1 core). Turning off the grid dropped the CPU use to 0. When the CPU is bogged down it's almost impossible for me to scroll the map or do anything meaningful. So I had to turn off the grid to do all my edits at which time the editor was very responsive.
Also in the editor when you mouse over an item none of the bonus's are listed. It shows the numbers but not the icons so you don't know what the bonus is for the item.
KGB