platform: Win7x64 SP1.
There could be situations when building silhouette/blueprint (that semi-transparent building that appears when you are choosing where you want to build something new) and mouse cursor are not in the same place. If you left-click the worker will start building where the cursor is (not blueprint).
To reproduce, select a worker, press 'Build Basic', then any building
then move the camera with arrow keys on the keyboard while not touching the mouse (mouse cursor keeps its position relative to the camera, while building silhouette gets redrawn only when you move the mouse cursor).
