title: delete font created by CreateFont
body: <p>If I use CreateFont() to create a font  (as non-static variable) and use SelectObject to use itin a function, then before exit that function, I have to select the previous object and use DeleteObject to delete the font.</p>
  
  <p>But if I declare a global variable <code>HFONT gFont = CreateFont(...)</code>, then in the <code>WM_DESTROY</code> message, should I call <code>DeleteObject</code> to delete the font?</p>
  
  <p>Also in this case, if I use <code>hOldFont = SelectObject(memDC, gFont);</code> in a function, should I call <code>SelectObject(memDC, hOldFont);</code>before exit that function? It seems to me that, for Bitmap, we should do this clean up, but I don't know if this is true for other GDI objects.</p>