Window just won't update!

I have a window. When a message is sent to it I process the message and then I want to redraw the window.

So. I do the following --

InvalidateRect( hwnd, NULL, FALSE );
UpdateWindow( hwnd );

And suprise suprise it doesn't update!! Why? Depending on the information this window has it will draw differently. In this message I have changed a variable and so the window should look different. I've even tested the variable and it's right!

The variable is declared outside of the case block and is declared as static?

It's not a problem with the variable. At least it shouldn't be. It works on other update times but just not on this specific one which is really weird....

Can you post a short bit of code that demonstrates the problem?

Code:

---

case MCC_ADDTAB: {
         
          if( ts->active >= 0 ) {
            ShowWindow( ts->pages[ts->active], SW_HIDE );
          }
          ts->active++;
          ts->nTabs++;
          ts->ids = (int*)realloc( ts->ids, ts->nTabs*sizeof(int) );
          ts->titles = (LPSTR*)realloc( ts->titles, ts->nTabs*sizeof(LPSTR) );
          ts->pages = (HWND*)realloc( ts->pages, ts->nTabs*sizeof(HWND) );
          ts->ids[ts->nTabs-1] = lParam;
          ts->titles[ts->nTabs-1] = (LPSTR)wParam;
          ts->pages[ts->nTabs-1] = CreatePage( hwnd, 1 );
          ts->set = true;
          SendMessage( GetParent( hwnd ), MCC_TABSEL, (WPARAM)ts->titles[ts->active],(LPARAM)ts->active );
          InvalidateRect( hwnd, NULL, FALSE );
          UpdateWindow( hwnd );
          return 0;
        }

---

In my WM_PAINT function depending on the value of ts->active it'll do something different. It works if I set it in other message cases but not this one for some weird reason.

No matter I've fixed it... somehow. :\