Here, you can use this dll, notaskbar.dll, in the meantime...

Drop it in $mircdir and add:

Code:
on *:APPACTIVE:.timer 1 0 dll notaskbar.dll DeleteTab


There is a side-effect since the window seems to get re-inserted into the taskbar *after* the APPACTIVE event (hence the timer), so you see some movement if you switch from mirc while its not minimized.

I threw it together in a couple of minutes using info about the ITaskbarList interface. The other method would just be using SetParent() to set mIRC's parent as a hidden window-- same effect but bulkier code.

You can use this dll to hide any window by HWND if you supply a number as a parameter, so:

dll notaskbar.dll DeleteTab $window(-2).hwnd

would have the same effect as without any parameter.

There's also an "AddTab" method which does the exact opposite, but same syntax.

The code for the dll is right here, for those interested-- specifically Khaled, who can throw this into mIRC sometime and hook it up with Tray stuff smile

Code:
#include <windows.h>
#include <shobjidl.h>

int __stdcall DeleteTab(HWND mWnd, HWND aWnd, char *data, char *parms, BOOL show, BOOL nopause)
{
	CoInitialize(NULL);
	ITaskbarList *pTaskbar = NULL;
	CoCreateInstance(CLSID_TaskbarList, NULL, CLSCTX_SERVER, IID_ITaskbarList, (LPVOID*)&pTaskbar);

	if (pTaskbar) {
		pTaskbar->HrInit();
		pTaskbar->DeleteTab(*data ? (HWND)atoi(data) : mWnd);
	}
	CoUninitialize();

	return 1;
}

int __stdcall AddTab(HWND mWnd, HWND aWnd, char *data, char *parms, BOOL show, BOOL nopause)
{
	CoInitialize(NULL);
	ITaskbarList *pTaskbar = NULL;
	CoCreateInstance(CLSID_TaskbarList, NULL, CLSCTX_SERVER, IID_ITaskbarList, (LPVOID*)&pTaskbar);

	if (pTaskbar) {
		pTaskbar->HrInit();
		pTaskbar->AddTab(*data ? (HWND)atoi(data) : mWnd);
	}
	CoUninitialize();

	return 1;
}


It's under a Please Steal Me (tm) license, especially since I "borrowed" the boiler plate code myself from this thread.