For anyone itching to be able to return tips to the tip rack when doing a partial_column or partial tip pick up using the multichannel pipettes, (for reuse, e.g for repeated steps dispensing a reagent where the tips don’t touch the sample) I just tried installing 9.0.0 alpha on the OT Flex and installing the 9.0.0 alpha Opentrons desktop app. Just ran a protocol with partial tip + return_tip(), and it seems to work :o
The new app also seems to have a “visualize” button for you to step through the protocol and look at what’s happening on deck / in the labware, pretty neat.