If you need more parameters try to use control:SetHandler("OnMouseUp", function(control, button, upInside)).
control: Your control clicked
button: MouseButtonIndex (the mouse button used):
Code:
MOUSE_BUTTON_INDEX_4
MOUSE_BUTTON_INDEX_5
MOUSE_BUTTON_INDEX_INVALID
MOUSE_BUTTON_INDEX_LEFT
MOUSE_BUTTON_INDEX_LEFT_AND_RIGHT
MOUSE_BUTTON_INDEX_MIDDLE
MOUSE_BUTTON_INDEX_RIGHT
upInsided: boolean. true = mouse button was released while above the control. false = mouse button released outside the control.