EDIT

ref #7715 re-enable source section in supplemental view for descriptions

fix #7871 Open character matrix as singleton

ref #7869 Run request for availabel ontologies in background task

ref #7869 Run ontology search in background task

fix #7868 Allow creating a new vocabulary in vocabulary selection dialog

ref #7806 Do not set dirty flag when voc selection was canceled

ref #7806 Add warning for long running searches

code refactoring + typo

ref #7844 Show fail text when connection times out

Merge branch 'release/5.4.0' into develop