If you want to switch from one selected namespace to another, you cannot remove the old one with backspace, you have to add the new namespace (which even doesnt show up pinned at the top), but click out, click in again and deselect the old namespace.
So the current user experience is really shitty tbh, sorry.
Could you provide something like selectize? Easy to remove single namespaces:
Hello h0jezvgoxfepbq2c,
Thank you for reaching out to Lens forum!
I’ll let the dev team related your suggestion.
Thank you for the feedback!
Best Regards,
Tikhon Kudinov
Lens Support Engineer
Mirantis, Inc
I liked the old version. If I click on a namespace, only that namespace is selected and the dropdown closes. If I click on the checkbox next to the namespace, it means I want to select multiple and I have the option to select multiple.
Yes, please 
I have 40 namespaces and my team has had 2 incidents since updating
Hi, in the next version the Namespace selector will not close when a Namespace is selected.
Thank you for your feedback.