Mirek,

OK, it seems the following (along with the previous changes) fixes Splitter behavior with pen.

Splitter.h:

class Splitter : public Ctrl {
	int            pointer;
public:
	virtual void   Layout();
	virtual void   Paint(Draw& draw);
	virtual void   DoMouseMove(Point p, dword keyflags);
	virtual void   MouseMove(Point p, dword keyflags);
	virtual bool   Pen(Point p, const PenInfo &pn, dword keyflags);
	virtual void   LeftDown(Point p, dword keyflags);
	virtual void   LeftUp(Point p, dword keyflags);
...

Splitter.cpp:

...
void   Splitter::MouseMove(Point p, dword) {
	if(pointer==2) DoMouseMove(p,0);
}

void   Splitter::DoMouseMove(Point p, dword) {
	if(HasCapture() && mouseindex >= 0 && mouseindex < pos.GetCount()) {
		SetPos(ClientToPos(p), mouseindex);
		Refresh();
		WhenAction();
	}
}

bool   Splitter::Pen(Point p, const PenInfo &pn, dword keyflags){
	switch(pn.action){
		case 0:
			if(pointer==1 && !pn.history) DoMouseMove(p, keyflags);
			break;
		case PEN_DOWN:
			if(IsNull(pointer)) pointer=1;
			LeftDown(p, keyflags);
			break;
		case PEN_UP:
			LeftUp(p, keyflags);
			break;
	}
	return true;
}

void   Splitter::LeftDown(Point p, dword) {
	if(IsNull(pointer)) pointer=2;
	SetCapture();
	Refresh();
	mouseindex = FindIndex(p);
}

int Splitter::FindIndex(Point client) const {
	int best = -1;
	int maxdist = chstyle->width;
	for(int i = 0; i < pos.GetCount(); i++) {
		int dist = abs((vert ? client.y : client.x) - PosToClient(pos[i]));
		if(dist <= maxdist) {
			best = i;
			maxdist = abs(dist);
		}
	}
	return best;
}

void   Splitter::LeftUp(Point p, dword keyflags) {
	pointer=Null;
	if(HasCapture())
		WhenSplitFinish();
	ReleaseCapture();
	Refresh();
}
...
Splitter::Splitter() {
	pointer = Null; // << Initialize here
	chstyle = NULL;
...

Best regards,

Tom