[TreeView] Gmail sample's css isn't correct when selected #20125
Description
- The issue is present in the latest release.
- I have searched the issues of this repository and believe that this is not a duplicate.
Current Behavior 😯
It's not a bug but only a css problem. In Gmail Clone sample, backgroundColor: transparent was overridden by the default one which causes the background not pure.
How about change it to backgroundColor: 'transparent !important',?
