Wan - interesting; that should explain it then. Not sure if we'll be able to come up with a fix that doesn't bring back the too-many-files-open bug, though, so given WM's excellent multitasking abilities we may end up leaving this as is.
HW60 - that fits with other reports in this thread; seems like for whatever reason some keyboards do funny things to screen input that screw up handwriting strokes. Might involve finger input in some way, the optimizations to map thumb taps to keys more accurately could also be preventing pen movements from showing up in Pleco correctly.