Why can't I create units?

sometimes I can't create units
I get to step 3 and it don't work.
I try to select a base but nothing happens
Are there restrictions to making units

sometimes the "list" doesnt work. You keep pushing the name of your O base but it doesnt populate in the little window below. Bug.

And you cant see the base either removing the ability to direct click the O base

What I find I have to do is move my units out of the way of the base, then sadly dismantle all supply units, so they too are out of your way.

Then you can see the O base.

CLick O base ON THE MAP at step three then finish. Should work.

If you have another tab/page of simcountry open while you try to use create the unit at a base; it will not work. You need to close all other tabs/pages. Then it will likely work. I have had the problem for years on chrome.