Can only add ene device per internal at a time?

Richard, I’m seeing an issue where I can only add one device per interval in an action at a time. If I try to add more than one, all but the first are not saved. I have to exit out of the editor, go back in, and add the subsequent devices. Is this a known issue?

PLC 8.21
PLEG 8.11
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Are you using the advanced mode or graphical mode ?

Advanced, typically - but I think I’ve tried both.