Ok, this was started from a bug that canvas getting not be updated.
If map is just disabled, at least one frame in the map region should be redrawn
So I added a condition 'map changed' in the render even though map is off
status. Now, I got a performance regression issue because it makes dirty
region is always true for the map object.
That is a corner case acutally, that object is not rendered but map still
have changed status.
I replaced the condition only if object is changed + map is changed.
At least, my test case works better with this patch.