OK, downloaded and runs.
First thing, it looks good, I don't often use the IDE but when I do I'm inclined to use this one just because it is a more modern look and feel.
There is a list of examples in the right panel, how do you load them? Clicking, double-clicking, clicking the "Clone" button all have no obvious affect.
So to get some source code I ran the normal IDE to get the blink sketch.
It fails to compile
INFO: assembling sketch in directory: C:\Users\Rob\Documents\Arduino\Blink
INFO: using temp dir: C:\tmp\blah
INFO: generating C/C++ file: C:\tmp\blah\Blink.cpp
INFO: error!
INFO: null
INFO: java.lang.NullPointerException
at com.joshondesign.arduino.common.CompileTask.assemble(CompileTask.java:129)
at com.joshondesign.arduinox.Actions$2$1.run(Actions.java:73)
at java.lang.Thread.run(Unknown Source)
Turns out C:\tmp\blah\Blink.cpp does not exist, at least not after the event but it may have been cleaned up.
I just repeated the exercise and the first line is now
INFO: assembling sketch in directory: C:\ArduinoX\win
A different folder to the last time.
Also it doesn't remember the window location and size and ^A doesn't highlight all the text even though the menu option does. I assume the "Meta" key is not set for Windows? ^C and ^V work.
Rob