There is a problim where if you use a tome then a gold dot apears on the ground, after sevral of these appear it starts to lag the game pretty badly.
What this actualy is is the tomes death animation playing but not being removed.
There is a real simple fix for this.
Firstly put all the tomes in the same item folder. (I used the charged folder)
Now add this trigger.
Tome Fix
Events
Unit - A unit Uses an item
Conditions
(Item-class of (Item being manipulated)) Equal to Charged
Actions
Item - Remove (Item being manipulated)
This will remove the gold dots and stop the lag from ever happening.
Ps. Love your map