This is related to #1126...

It would be a much better UX if we had a "select pages" or "select content" link there that would open a browser (same view as admin/content minus the "Operations" fieldset) where people could simply search/filter, then point and click to select pages/paths:

backdrop-layout_visibitily_conditions-url_path

...I mean, all other options for visibility are fairly simple point-click:

backdrop-layout_visibitily_conditions-node_type

backdrop-layout_visibitily_conditions-site_language

backdrop-layout_visibitily_conditions-user_permission

backdrop-layout_visibitily_conditions-user_role

GitHub Link: 
https://github.com/backdrop/backdrop-issues/issues/1129
GitHub Issue #: 
1129