How to debug plugin source code in Xcode?
I have find the solution of this problem.
Just follow the steps for debug the Plugins code in Xcode.
Step 1 = Go to Edit scheme in your Xcode and go to Edit scheme = >.
Step 2=Select Run and info tab from side window and select Executable Application from the drop down list (in my case Mail app from Application->Mail)
Keep your application running ant try to debug your Plugin source code....... its works for me fantastic..
additional hint:
if you would debug a Xcode plugin, I found this:
Speedy37 commented on Sep 19, 2014:
With the default options you can't debug Xcode 6
Go to your debug options : Edit Scheme > Run > Optionsand uncheck "Enable user interface debugging" (DebuggerUI can't debug itself)
After I do this I could debug Xcode plugIn, before it crashed.