No idea what you are doing wrong, but here is a workaround.
Pin the Checkmark to the objects you want selectable, when you spawn them.
At spawn turn the checks invisible.
On mouse over set it to Visible 50%
On mouseover and left click, set to visible 100%
Invert a mouse over the checkmark, and set to invisible.
TL;DR, Use visibility, and toggle it on and off with clicks rather than trying to spawn one every time you need it.
If you add the Checkmark to a container, it will automatically destroy with the object it is parented to.
Hope that helps, my english is not so good.