I was doing a quick test program when developing a MT8050iE HMI interface.
I noticed a complier error when it reacts to this bit of code with a simple error in it.
I am running the latest Beta, latest Java on windows 7
When you do a compile to test the code, it apparently sees the code problem, and flashes the complier error message, but it remains on the screen for about 1/100 of a second (just a flash) , and then returns to the ladder screen, no error message etc.
If you didn't know the regular process it goes though compiling , you could be surprised.