This is not normal behavior. Usually a object is not seletable as you have stated above if it is behind another object, then you would bring it forward. I suggest running recover on this databases to rule out corruption.
There is no eror reported after I ran RECOVER. Anyway, I tried again to repeat the problem but I am able to click on the object after I set none to Fill and Line (see diagram).
The selection handles in both screen shots show that the field is selected.
Are you trying to select the field while in browse mode?
No "handles" will appear if you click it while in browse mode and if you are trying to select the field to insert a file into it, no cursor appears, but you'll find that if you right-click it, you'll get a list of options for inserting into the container field or you can left click it and select from the insert menu to insert into the field even though you don't see a cursor in the field.
It happens in Layout Edit mode. This strange "problem" is no longer exist. Thanks.