Selecting a GTOL can somewhat tricky depending on how you doing the selection and how the GTOL was made. For one made by selecting the Geometric Tolerance icon you can hover your mouse pointer over the reference frame, RMB, select the reference frame, RMB, and select properties from the RM menu that pops up. This should open up the GTOL definition properties dialog box. You can also set the filter selection to geometric tolerance and select the reference frame double click it or RMB and select properties from the RM menu which should bring up the GTOL definition dialog box. I believe you can also get a value dialog box for editing the tolerance value only but I'd have to check on that. Selection works the same as if you were selecting geometry. As you place your cursor over an item and select RMB the system cycles through the items that are behind the pointer. For a GTOL attached to a dimension if you place the mouse pointer over the reference frame, select it, RMB, and select properties you get the dimension properties because it is the parent which is the reason for the second RMB click to cycle to the next item the GTOL.
GTOLs created as annotation features are easier to edit. You select Edit Definition, select the GTOL from the definition dialog box, and select properties which opens up the GTOL definition dialog box. I can post pics of what I get when going through these selections.
