An edit made to features using the tools on the Feature Edit toolbar will create pending changes which need to be either saved or discarded. Discarding edits will undo the pending changes you have made since the last save.
Click on the Discard Edit Session 
command if you wish to discard your pending edits. The Discard Feature Edits dialog is invoked to confirm that you would like to permanently discard all pending edits on the current layer.
The Feature Layer will remain selected in the dropdown box after an Edit session has been discarded.