WM_SIZE doesn't work as intended

[Olly]

Hello! I hope that you can halp me with my particular problem.
I need to hide the mousecurser when the window is getting maximized and to display it again when the window gets restored.

Now i do the following:

			if (wParam == SIZE_MAXIMIZED)  //check whether the user has maximized the window
				
				{
				 memset(&devModeScreen, 0, sizeof(devModeScreen));
				 devModeScreen.dmSize		=			sizeof(devModeScreen);
				 devModeScreen.dmPelsWidth	=			screenWidth;
				 devModeScreen.dmPelsHeight	=			screenHeight;
				 devModeScreen.dmBitsPerPel	=			screenBpp;
				 devModeScreen.dmFields		=			DM_PELSWIDTH | DM_PELSHEIGHT | DM_BITSPERPEL;
				
				dwExStyle = WS_EX_APPWINDOW;	//hide all topper level windows
				dwStyle = WS_POPUP;					//remove the window borders
				ShowCursor(FALSE);						//hide the cursor
				fullScreen = true;			
				}
				
			else

				{
						dwExStyle=NULL;
						dwStyle = WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_SYSMENU | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
						ShowCursor(TRUE);		//show the cursor
						fullScreen = false;
				}

But this code doesn't hide the cursor at all! It first hides it and then shows it up again even though i put it into the else chunk.
I've already tried to use SIZE_RESTORED instead of the else and this has the same effect. Hence i think it's always calling for the SIZE_RESTORED. But why is it doing that? I'm not restoring it at all!

(I can't imagine this is not due to a wrong if/else formulation , I simply don't get it why it does that