Cannot use/see new panel plugin Button Control Panel

Grafana v.7.1.3

Objective: I want to use the Button Control Panel plugin to be able to do database actions on click.

Executed action

  1. Downloaded plugin zip
  2. Installed it in the folder defined in the .ini file
  3. Restarted Grafana
  4. Looked into plugin list
  5. Added a new panel to a dashboard
  6. Tried to change panel type to button

Expected behavior
3. Plugin is loaded (log line)
4. Plugin appears in plugin list
5. New panel appears
6. All panel types appear including new plugin button

Observed behavior
1 to 5: as expected
5: The Button pluging is classified as plugin and signed
6: Only standard panel types appear. When filtering to button, lists gets empty


Online instructions followed
https://grafana.com/grafana/plugins/speakyourcode-button-panel/?tab=installation

Update: After adding a further plugin, I can see the button plugin, but not the latest one

Just installed the multistat plugin in order to test if it behaves identical.

Observed:
Now the former( button) plugin it available. The new one (multistat) is shown in the plugin list, but not as a visualization option for a panel.