Bugfix: if something is rendered in MainView (without an explicit "goto" event), all tabs must be closed

buttons with (implicit) target "main", which has only an action attribut (no page-attribut) dont trigger an "goto" event (URL-Change) . before the bugfix the new content has been rendered in Main-Tab, but other open tabs remained open.
another example for grid=>modal=>new page (via button)
close modal: try/catch
Merge remote-tracking branch 'dsiebeck/feature/webui' into feature/webui
Fix Secret Manager in UI