No worries and since you came back can I offer you a piece of code that can very quickly reject all the trivial shape areas that do not require drawing when moving in your current code. You need to set the "dragging" flag to TRUE when you are moving a shape and set it back to FALSE when done dragging. I don't have the structures so you need to feed in x1,y1,x2,y2 into the two /* xxxxx */. So for each Area x1,y1 needs to be top left corner, x2,y2 lower right corner of the on screen minimum box around the shape. It puts an extra very fast test on redrawing a shape if the flag is set and I will leave you to work out what it does but it is commented :-) BOOL CanAreasOverlap (int Area1_x1, int Area1_y1, int Area1_x2, int Area1_y2, int Area2_x1, int Area2_y1, int Area2_x2, int Area2_y2){ if (Area1_x1 > Area2_x2) return (FALSE); // Area 1 completely to the right of Area 2 and can't overlap if (Area1_x2 < Area2_x1) return (FALSE); // Area 1 completely to the left of Area 2 and can't overlap if (Area1_y1 > Area2_y2) return (FALSE); // Area 1 completely below Area 2 and can't overlap if (Area1_y2 < Area2_y1) return (FALSE); // Area 1 completely above Area2 and can't overlap return (TRUE); // The two square areas overlap to some degree } /* Set the dragging flag to TRUE when moving a shape */ BOOL dragging = FALSE; OnDraw(CDC* pDC){ for (int i = 0; i < numberObjects; i++){ if ((!dragging) || CanAreasOverlap(/\* Moving shape is area 1\*/, /\*objects\[i\] shape is area 2\*/)) { objects\[i\]->DrawShape(pDC); } } } When you drag a shape and go to redraw In vino veritas

Actually the problem was related to the way of copying from srcHDC to ImageHDC. I have done like this: HDC svgDC = cairo_win32_surface_get_dc(surface); image.Create(width, height, 32); image.SetHasAlphaChannel(TRUE); HDC imageHDC = image.GetDC(); BLENDFUNCTION blend = { AC_SRC_OVER, 0, 255, AC_SRC_ALPHA }; AlphaBlend(imageHDC, 0, 0, width, height, svgDC, 0, 0, width, height, blend); image.ReleaseDC(); Best regards!

In addition to sending the exact keys directly as Richard described (I think that method is basically replicating what a keyboard would do if I'm not mistaken), there is another way of achieving this. Sending messages to the application's control directly. Windows allows this and it's relatively easy to get the controls' ID's to send messages to them. Use Spy++[^] to get control IDs and you can also intercept some messages to figure out how yours should be formatted. Once you have control IDs, you can send messages using the SendMessage()[^] method. Biggest problem with this method is that it's more of a hack than anything else. The control IDs are not guaranteed to be the same from one version of the software to the next.