I don't know what the proper keyword if for it, but I know it appears due to a certain setting within Inventor's Application Options > General tab > Selection area. When you check the box to enable this "Enagle Optimized Selection" option, it causes that little 'mini toolbar' to start appearing when you hover over any select-able objects in the graphics window. You can specify how long it should wait before showing this tool, and the location tolerance, which specifies how far away your cursor/pointer can be from objects for it to still recognize them and add them to the list of available objects to select.
Below is a screen shot of this setting within the Application Options.

If this solved your problem, or answered your question, please click ACCEPT SOLUTION.
Or, if this helped you, please click 'LIKE' 👍.
Wesley Crihfield

(Not an Autodesk Employee)