A DESCRIPTION OF THE PROBLEM :
On Windows platform, default drawing pipeline (D3D) processes multiple PaintEvent at initial drawing. This behavior does not occur on GDI pipeline (-Dsun.java2d.noddraw=true).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
compile and run attached sample code on Windows platform. This sample counts a number of paint() calls.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Green window is shown and "1" is printed on console.

ACTUAL -
Red window is shown and print "2" is printed on console.

This additional PaintEvent is unnecessary and may cause performance issue.