Revert "Revert "Revert "App sidebar: floating window"""

This reverts commit fa7b70d854f21054d3bf9a4f776bdff504ea4192.
Revert "Appbar Derp"

This reverts commit 5c0e32d7b09467c3f1b3f22ba686b50cd1da1afb.
Revert "App sidebar [1/2]"

This reverts commit 6fc3634f3ae4c0f881c7f834cf5bae9989986cb2.