You can already do this by selecting the columns to show - the Custom Properties show in the list with an @ before their name. Note that sometimes you need to scroll down the list for them to show.
The custom column selections is not remembered between sessions by the QMC, you would need to select that custom property from that list for every session. It would be an improvement if QMC could remember this setup between my sessions.
QlikSense August 2021 Patch 3 I created custom property and activated checkbox "Reload tasks" In a Tasks section I assigned property value to random reload task. I returned to the tasks list and in a "Column selector" not appeared any custom property. This work for stream and apps, but not for tasks.
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