can't select different dim style

I have problem selecting a different dim style.

First I couldn't change the dim style at all in Tool Settings. I click the dropdown, select another, but it reverts back to the first. 

Then I opened Dimension Styles dialog and clicked one at at time made them active, back to Tool Settings, change and update from library- then! it will change.

Seems I need to make a dimstyle local, before I can place it. And/or set it active in the Dim Styles dialog - not in Tool Settings.

Similar for all dim styles, out of the box and my custom.

Any help much appreciated.

Have restarted ABD, and in several files. Textstyles are ok.