C++ RealTimeStylus is dead and doesn't handle any touch messages

RL Chen 230

After some testing, I found that the RTS touch library on win7sp1 systems has a probability of triggering an error: RealTimeStylus does not trigger, i.e. it does not trigger the touch callback class even if there is a touch point that has been pressed on the corresponding window. This problem disappeared after restarting the program, but it was caused by the fact that after starting the program, another program opened a full screen window and grabbed the focus, and then my program RTS died as if it didn't process any touch messages (my bound window was still on the top level). At the same time the RTS bound window has WS_EX_LAYERED and WS_EX_NOACTIVATE and HWND_TOPMOST and does not remove these flags. I am using C++.

Xiaopo Yang - MSFT 12,231 Reputation points Microsoft Vendor

2024-04-03T07:21:17.2833333+00:00

Hello @RL Chen, win7sp1 support has expired. Can you reproduce it using Windows11? And could you please show reproducible steps using the MTScratchpadRTStylus sample or a minimal sample?
RL Chen 230 Reputation points

2024-04-04T05:25:53.58+00:00

@Xiaopo Yang - MSFT I'm very aware of this, and I'm in the process of trying it out, but I'm not sure what I can do to reproduce this problem. But after three days of research, the current idea is to pop up a MessageBox in a window labeled WS_EX_NOACTIVATE, which should get the focus, and then close it so that the original WS_EX_NOACTIVATE form should get a focus https:// developercommunity.visualstudio.com/t/C-WS_EX_NOACTIVATE-Window-was-incorrec/10631362, then RTS is dead until you click on the taskbar to give focus to Shell_TrayWnd. RTS is dead until you click on the taskbar and give focus to Shell_TrayWnd. The RTS window has HWND_TOPMOST, which causes the RTS to not receive and process any touch messages when I touch the window again while the RTS is dead. This problem only seems to occur on the touch screen, using the mouse doesn't seem to trigger it. For the OS, I can't say for sure, but more currently, it seems to have a higher probability of occurring in win7sp1. I'll send something new when I've looked into it later.
Xiaopo Yang - MSFT 12,231 Reputation points Microsoft Vendor

2024-04-05T02:47:36.6266667+00:00

It's better to show code snippet with us. And according to WS_EX_NOACTIVATE,

... To activate the window, use the SetActiveWindow or SetForegroundWindow function. The window does not appear on the taskbar by default. To force the window to appear on the taskbar, use the WS_EX_APPWINDOW style.

It's possible to make it active.

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C++ RealTimeStylus is dead and doesn't handle any touch messages