This issue has been reported multiple times already but to my knowledge (and certainly in my experience) has not been addressed. The mouse freezes during indexing, often for 5-10 minutes at a time. I can't always wait to download at night if I need a resource now and it is actually more time efficient to index while doing something else on the computer. But the mouse freezes (nothing else). There is only so much that can be done using keyboard shortcuts and tabbing around.
The indexing process priority is already set to low, yet I can hear my fan go on when I index. My laptop is 2 years old, with an i5 processor and 8 gb of RAM, plenty of HDD space.