Revert 51506ab..0652dfc

This rolls back to commit 51506ab874cc9a70effb60cc4c3eeb6564d3c0ee.
Merge branch 'SidneyFan' into version3.0
Frame Margin
Merge branch 'version3.0' of https://github.com/FudanSoftwareCCWI/Lab4 into version3.0
Merge branch 'ArielQian' into version3.0
Merge branch 'version3.0' into ArielQian