I have a 24" external monitor hooked up to my rMBP as a secondary display. Since upgrading to 10.9, the new "Multiple Display feature" has made opening apps a pain in the ass. It seems that which ever display the dock is on is the display the app window will open in. Makes sense but this is extremely stupid for those who want to launch apps from the primary display and have them open on the secondary display. Even after repositioning the app window where I want it, quitting and reopening the app causes it to open on the primary display again. It doesn't remember the last position like it used to in Mountain Lion. I've found a semi-fix and that is to add a new desktop space to my secondary display, right click on the app in the dock, choose options and then select "Assign to...desktop on display 2." This "fix" however only puts the window on the secondary display - it still resizes it and moves it so I still end up dragging it where I want it. Another fix is to invoke the dock to the secondary display and then launch the app, however the dock cuts off the bottom part of the window so I STILL have to resize the window. The only fool-proof fix right now is to invoke Spotlight search on the secondary display and use it to launch the app. THEN it will open where it is supposed to. tl;dr - the multiple displays feature is a pain in the ass when opening apps.