This is not a snapping issue. I have ALT clicked to no avail. Plus there is no vector data in the Zoom View window.
Basically when I try to add a GCP to the ZOOMED VIEW window the point is placed about 10 pixels away. There is no vector present. This is a raster image.
This is how I got to this point.
Loaded shape-files (lat/long).
Loaded a dumb TIF and choose to rectify it.
I used the shape-files to pick the GCPs.
Changed the projection to match the raster and saved PRJ file.
Selected triangulation as method.
Saved the GCP file (just in case).
Clicked OK in the Image Rectifier and viewed in the main window.
Saved the workspace (which I see saves the GCPs inside the GMW file).
Opened the GMW workspace next day.
Opened the Overlay Control Center and right-clicked on the TIF layer to Modify Layer Position/reprojection.
Added a few more GCPs. It was after a few iterations of this that I noticed that despite the triangulation method some GCPs seemed to be ignored as the raster and vector did not match at that point (PROBLEM 1). When I went back into the Rectifier Tool I had to UPDATE the points as they had moved off the GCPs slightly (PROBLEM 2). Also, when clicking in the Zoomed View (TIFF) the point would be offset about 10 pixels from the cursor axis (PROBLEM 3).
Note: I never exported the TIF to a file. I left it in its original form. Once I am happy with the rectification I will export it. But wondering if the constant "Modify Layer Position" is destructive or have I run into a limitation with the projection algorithm? It is Lambert Conic.