SetWindowPos behaviour for Notepad.exe on multi-moniter setup

Question

Hi. I saw some strange behaviour while trying to move Notepad window using SetWindowPos. The issue is that in multi-monitor setup, when I pass x=-1 to SetWindowPos call, the window not only moves in x-direction, but also move in y-direction (sort of creeps up). It happens on other windows like browsers etc. I would like to know why is this the case? (since this doesn't happen when I drag the window with the mouse across the monitor boundary)

I have posted the question with screenshots on stackoverflow here: https://stackoverflow.com/questions/71751167/setwindowpos-behaviour-for-notepad-exe-on-multi-moniter-setup

Answer 1

Is it normal in C++ console program? because I did not reproduce your problem.

#include <Windows.h>  
#include <iostream>  
  
using namespace std;  
  
int main(void)  
{  
	HWND mhwnd = FindWindow(L"Notepad", NULL);  
	RECT rc;  
	GetWindowRect(mhwnd, &rc);  
	cout << "1:(" << rc.left << "," << rc.top << "," << rc.right << "," << rc.bottom << ")" << endl;  
  
	SetWindowPos(mhwnd, HWND_TOP, 0, 200, 200, 100, SWP_NOREDRAW);  
	GetWindowRect(mhwnd, &rc);  
	cout << "2:(" << rc.left << "," << rc.top << "," << rc.right << "," << rc.bottom << ")" << endl;  
  
	SetWindowPos(mhwnd, HWND_TOP, -1, 200, 200, 100, SWP_NOREDRAW);  
	GetWindowRect(mhwnd, &rc);  
	cout << "3:(" << rc.left << "," << rc.top << "," << rc.right << "," << rc.bottom << ")" << endl;  
  
	SetWindowPos(mhwnd, HWND_TOP, -1, 60, 200, 100, SWP_NOREDRAW);  
	GetWindowRect(mhwnd, &rc);  
	cout << "4:(" << rc.left << "," << rc.top << "," << rc.right << "," << rc.bottom << ")" << endl;  
  
	SetWindowPos(mhwnd, HWND_TOP, -1, 600, 200, 100, SWP_NOREDRAW);  
	GetWindowRect(mhwnd, &rc);  
	cout << "5:(" << rc.left << "," << rc.top << "," << rc.right << "," << rc.bottom << ")" << endl;  
  
	return 0;  
}