after brushing an area, cant open the edited area again by klicking on blue dots, its gone?

After editing an area with the brush (light, color .. what so ever..) there was usually a blue dot, on which i could click to change it again. 

It's gone now. 

on mac, there's an option in the bottom left corner "show always" or something like that.

but that's missing on windows version. 

can anyone help me ?

how do I get the "blue dots" back on which i could click to open the edited area? 

thanks everyone!