Want to ask, is my own made the player GUI, load the file, the mouse focus is not on the program, this time I'll use shortcuts (I set up the blank space key is playing), found the program automatically opens the load file and select box, need to check the application can use the blank space key play, want to know what the unity with function can be achieved after the choice the file to the mouse focus on receiving program automatically, make the realization of the function of the keyboard shortcuts, please!