TOPIC:

If the grid is on, then switch it off, because your door may be attempting to snap to the grid as well as to the wall or guideline.

Placing a guide line is normally the solution for precise placement but note that it is the centre of the door that snap to the guide line.

Alternatively use the Construction Support tool:
1. Select the door to place
2. 2. Before clicking to place the door in the wall, right click and select Construction Support the pop up context menu, and select one of the placement options, or press the A key, which will allow you to place the CENTRE of the door from a specified point.

Construction Support Tool Video

Also make sure you are using the doors in the left hand tool bar, and not from the 3D catalogue. Although it is possible to place doors in the 3D view, it is always easier to place in a 2D view.

See also A simple project video

I am trying to place a door in a particular position within a wall but seem unable to locate it in the right place. Have added a grid line but the snap function places it everywhere except to the edge of the line. Dragging it with mouse click just seems to move it to completely random places. Just getting started with VB so no expert.