The "edit the number of vertices in the object" menu closing, help

Hey guys, I am trying to edit number of vertices on fresh “spawn” Ico Sphere, and its closing right after I change value to “2”, I am pressing f9 to repeat and this menu is gray color, non selectable. Same goes with every mesh I add. Please help!1

Have you tried pressing F6?

Not only does mine stay open,
it only becomes unusable after I edit the object (icosphere)

Please give more detail, maybe a (very short) video