Hmmm, in FileMaker 11 on Windows XP, If I drag a selection box around a locked object, it IS selected, just as in FileMaker 12. BUT, if I click and drag on a locked object in FileMaker 11, it is not selected and it IS selected in FileMaker 12 due to the change in selection box behavior. If I hold down the control key, I get the original selection box behavior and identical results for my locked object as compared to using the selection box in FileMaker 11.
But in testing this, I encountered a slightly different bug.
I had a locked button object on the layout for my test that was adjacent to a portal. The Portal and objects within it were not locked. When I dragged a selection box (no control key modifier used) over the locked button, it was selected UNTIL, the box touched the portal. Then the portal was selected, but the locked button was instantly deselected!
Further tests revealed that the objects do not need to be adjacent and that this also occurs when holding down the control key (but now the locked object is "dropped" from selection only when the selection box encloses an unlocked layout object.)
On further thought, I don't think what I found is a bug. If I lock a tab control and then drag to select objects on the tab control, the locked object is initially selected, but once my selection box selects an unlocked object, it drops the tab control and I am able to select the unlocked objects on the tab panel so that I can work with them as a selected group...
I went from FMP10 to FMP12 and in version 10, a drag/select did not get that locked tab control. This is what I was used to. It didn't occur to me to try a modifier key. In FMP12 on Windows, the CTL key does in fact mimic the behavior I had been used to in version 10. What I did like about the drag selection in version 12 is that you did not have to completely encompass the target items. It was sufficient to simply touch any part of item's surrounding box (very convenient), but then since the tab control is "touched" as well, it make sense that it would be captured..... but, it seems that locking an item ought to exempt it from this type of action.
Yet sometimes we want to select a group of locked objects so that we can unlock the locked items.
It looks to me that this is an intentional behavior change and, IMO, a fairly reasonable compromise. Note that when I try this, the locked objects are not selected once the selection box selects an unlocked object.