Java Swing repaint

[sz20b]

I develop an image editor program, with java swing. There is a button for add/remove "pixel grid" (showing each pixels), I use here repaint() for redrawing the screen with pixel grid.
My problem is that it works in many PCs, but there is several, where this repainting is very slowly, it takes minutes.
I don't know what can be the problem...
Can anybody help, me?

[DarrylBurke]

Possibilities:
-- There's a bug in the code you haven't showed us
-- The Graphics driver isn't up to date
-- Anybody's guess

To get better help sooner post a SSCCE (Short, Self Contained, Compilable and Executable) example that demonstrates the problem. Also post the hardware, OS and Java version information for the PCs on which you tested and indicate which of them experience the slowdown.

db