Interest in overhauling the IDE user interface?

Development Suggestions for the Arduino Project
99

Trying to compile "blink"

starting compile
assembling sketch in directory: C:\ArduinoX\win
using temp dir: C:\Users\Rob\AppData\Local\Temp\josharduinobuild1498449018706449586.tmp
generating C/C++ file: C:\Users\Rob\AppData\Local\Temp\josharduinobuild1498449018706449586.tmp\.cpp
error!
null
java.lang.NullPointerException
	at com.joshondesign.arduino.common.CompileTask.assemble(CompileTask.java:130)
	at com.joshondesign.arduinox.Actions$2$1.run(Actions.java:74)
	at java.lang.Thread.run(Unknown Source)

Vista, 32-bit, Arduino 1.0.2 I guess but I also have 1.5 installed, how does it know which one to use?

Note the CPP filename.

Rob