BF: Move code to set stdout to the Runner to showRunner, fixes #3105.…

… Elementary, my dear Watson.

psychopy/app/_psychopyApp.py

@@ -427,10 +427,6 @@ def onInit(self, showSplash=True, testMode=False):
         # we wanted debug mode while loading but safe to go back to info mode
         if not self.prefs.app['debugMode']:
             logging.console.setLevel(logging.INFO)
-        # Runner captures standard streams until program closed
-        if self.runner and not self.testMode:
-            sys.stdout = self.runner.stdOut
-            sys.stderr = self.runner.stdOut
 
         return True
 
@@ -593,6 +589,10 @@ def showRunner(self, event=None, fileList=[]):
             self.runner.Show()
             self.runner.Raise()
             self.SetTopWindow(self.runner)
+        # Runner captures standard streams until program closed
+        if self.runner and not self.testMode:
+            sys.stdout = self.runner.stdOut
+            sys.stderr = self.runner.stdOut
 
     def newRunnerFrame(self, event=None):
         # have to reimport because it is only local to __init__ so far