Add some more styling to trees to clarify which node one currently hovers.
Add some more styling to trees to clarify which node one currently hovers.

Signed-off-by: Jan Bicker <98f56abcfcb7eb45a59402641e1c79a8fb6d875f@typefox.io>

epatpol/theia-1,epatpol/theia-1,epatpol/theia-1