When applying a conditional formatting rule in Excel, using the "Edit Formatting Rule" dialog, and using "Use a formula to determine which cells to format," you cannot move the caret (text insertion point) in the formula editor with the keyboard. If you try to use the arrow keys it inserts the cell name next to the cell in focus depending whether you hit the up/down/left/right key. Is there some way to turn this off? or some way to move the caret with the keyboard?
After you enter your formula, press F2 to which will enable edit mode allowing you to move the cursor with the arrow keys.