How to enable the highlighting of selected objects or text? It just stopped highlighting in only one drawing, but a real pain. It is still "selecting" them, just not visually indicating the selection.
If it's happening only in one document, select all, copy, and paste into a new doc.
Something in the original doc is causing some corruptions or other.
If this still fails, try resetting your prefs.
I can also imagine that you just inadvertently hid the Edges and perhaps Smart Guides.
You may check if View menu > Show Edges and/or View menu > (Show) Smart Guides can help.
Or View menu > Show Bounding Box.
Kurt! You know da kine mo betta adobe stuffs for sure !!!
Turn on da edges !!
Try Ctrl/Cmd + H.