Blender 2.91 alpha - I can't select in edit mode?

Hi. Just downloaded the latest Blender 2.91 alpha build from https://builder.blender.org/download and in edit mode seems that I can’t make any kind of selection.

Please can somebody confirm this strange behaviour? I even deleted the stored settings and made a clean install on my MacBookPro with MacOS 10.15.5 and the same!