I recently encountered two bugs at once:
The first is most obvious: the MessageBox that has popped up with the name of a ship (or fleet) in it. I don't know the exact trigger for this; it certainly does not happen every time a ship goes through a jump point, or even every time a new system is discovered. However, it did happen while the named ship (or fleet) was discovering a new system, so it does seem related to that event, or to generating the new system.
The second bug is more subtle. Behind the MessageBox, the tactical map is drawn incorrectly. In fact, it appears that the MessageBox is interrupting a process that redraws the tactical map multiple times with different data.
First, the system that the ship is leaving is being drawn, rather than the system that the ship is discovering. Second, the position of the ship is incorrect; it should be on top of the jump point. Perhaps this position is stale, and comes from the previous sub-pulse. This ship just launched those two missiles, then outraced them to the jump point (they're obsolete first-generation missiles; I must have made too many), so the ship's position has definitely been updated at least once since the start of the turn. Lastly, the lines that indicate motion are drawn incorrectly. The ship and missiles are actually moving SSW, not NNE. It looks like this is happening because the start of the line is drawn in the coordinate system of the destination star system; the jump point in the destination star system is due south of the star, and the start of that line is due south of the star in this system (it's behind the MessageBox, of course). Likewise, the missiles moved from a point to the NNE of the star in this system, and the start of their line is to the NNE of this star but at the wrong distance from the center because the scale is different.
It looks like some of the flickering during window updates is happening because the window is drawn and cleared multiple times. I don't know the Windows API very well, but I believe that you should be inhibiting paint events while updating the window. Even better I think you should use double-buffering, at least for the graphical elements if not the UI widgets.
