I'm not sure if this is directly Slack-related or more Xfree-related so I prefer to ask some questions here first before bothering Pat Volkerding.
Here it goes : I work (that is my wife, actually) on an animation short movie project using Gimp as the main creative tool and we use quite a lot the video plug-in of Gimp, especially the VCR Navigator and the Frame Convert plugin.
However, using Slackware 9.0 with Xfree 4.3, we ran into memory consumption issues of the X process (esp the VIRT memory displayed by top). Each time a frame is loaded using the VCR Navigator or for a massive Frame convertion, the X memory occupation increases. After a day of work, it's usually close to 1GB.
Reverting to the old Slack-Current Xfree 4.2.1 package solved this.
Have you experienced such kind of problem and do you think it could just be a build issue? I tend to see it more like a Xfree bug but I would be interested in other opinions.
Of course, I could keep using the 4.2.1 packages, but I like these ridiculous animated cursors. :-)

Best regards,