Collection editor issues when trying to define a custom query

[JJ-Author]

• click on query name in tree view brings 404
• add button is hard to see and easy to overlook (need to scroll down) when clicking preview the query i just wrote is gone (when not pressing add before, without any warning
• no button to delete a custom query
• when there is an error with publishing the collection (e.g. you picked name of an already existing collection because of another bug) no error message is there, one is totally lost
• when trying to add another custom query nothing happens no error / no success