[demo] navbar subitem shifted to top-left corner

Steps to Reproduce

http://zktest:8089/zkdemo/zk_pe_and_ee/menu_navbar

Theme: Iceblue Compact

Orientation: horizontal/vertical + Collapsed 

1. Hover on to the navbar 
2. Notice the sub-header shifted to the top left corner, unnecessary gap between sub-header and first item

Only happens in Iceblue Compact
Checked with Chrome/Safari

Current Result

Expected Result

Debug Information

Workaround