Christian Shaw has asked the Select Triangle tool to be active after you delete selected triangles.
I think it maybe complicated as now after you select triangles you need to use another tool to delete them. Maybe a Del button to delete the selected triangles may keep the Select Tool active?
JIRA Ticket
https://hypack.atlassian.net/jira/servicedesk/projects/SUP/queues/custom/32/SUP-3542