Moved handling of "user" changelabel errors out. ChangeLabel done through the...

Moved handling of "user" changelabel errors out. ChangeLabel done through the edit action always completes successfully or throws an error. This makes sure that the graph edits only get set when the change works.

src/MATLAB/+Editor/ContextChangeLabel.m

@@ -40,6 +40,17 @@ function ContextChangeLabel(time,trackID)
     end
     curHull = CellTracks(newTrackID).hulls(1);
     
+    if ( newTrackID == trackID )
+        warndlg('New label is the same as the current label.');
+        return;
+    end
+    
+    if ( time < CellTracks(newTrackID).startTime )
+        warn = sprintf('Cannot change label from %d to %d, track %d does not exist until frame %d.',trackID, newTrackID,newTrackID, CellTracks(newTrackID).startTime);
+        warndlg(warn);
+        return
+    end
+
     bErr = Editor.ReplayableEditAction(@Editor.ChangeLabelAction, trackID,newTrackID,time);
     if ( bErr )
         return;

src/MATLAB/+Tracks/ChangeLabel.m

@@ -6,19 +6,16 @@
 
 % ChangeLog:
 % EW 6/7/12 created
-function droppedTracks = ChangeLabel(currentTrack, desiredTrack, time)
+function [droppedTracks bErr] = ChangeLabel(currentTrack, desiredTrack, time)
 global CellTracks
 
+bErr = 1;
 droppedTracks = [];
 
 if (~exist('time','var'))
     time = CellTracks(currentTrack).startTime;
 end
 
-if (time<CellTracks(desiredTrack).startTime)
-    return
-end
-
 children = CellTracks(currentTrack).childrenTracks;
 
 %Pass the work off to the lower function
@@ -29,4 +26,6 @@ if(length(intersect(droppedTracks,children))==2)
     Families.ReconnectParentWithChildren(desiredTrack,children);
     droppedTracks = setdiff(droppedTracks,children);
 end
+
+bErr = 0;
 end
\ No newline at end of file