When Following Earth, and the Milky Way is Selected, turning on Markers makes the Sun, planets and their orbits disappear when viewed from some positions.
This problem is seen in r4624. It is seen as far back as r4495. (I can't test earlier svn versions.)
This problem is not seen in v1.5.1
This problem is not seen in r4624 if "Label Planets" is enabled.
This URL demonstrates the problem. It takes you to a viewpoint just outside the solar system, with markers disabled. When markers are enabled (type a ctrl-K) the solar system disappears. If you move the viewpoint somewhat closer to the solar system, the solar system does not disappear when markers are enabled.
Note also that the "Selected" marker is not being drawn, presumably because the viewpoint is inside the Milky Way.