In DraftSight, something weird has happened to my settings. Probably it is just a matter of selecting/deselecting a check mark somewhere. Anyhow, this is really annoying me.When drawing any figure with Esnap (F3) and Etrack (F11) switched on and with Ortho (F8) switched off, I get a horizontal/vertical tracking line every time I move the pointer to a midpoint, endpoint etc., for instance when drawing a standard rectangle. But if I do with Ortho switched on, the tracking line never pops up.Can anyone tell me how to make this tracking line pop up regardless of the Ortho function being switched on or off?

If orthomode is enabled why would you need a tracking line to draw a line up, down, left or right?  You're basically locked in.

I need an entity tracking line with ortho ON because the line which I am actually drawing has to point exactly in direction 0, 90, 180 or 270 degr.

Maybe I'm not following you here but doesn't having orthomode enabled practically guarantee that lines can be drawn at 0, 90, 180 and 270 degrees?

Yes it does but if I want to make my line stop in a position perpendicular to a certain point, then I can't make use of a tracking line due to the fact that it simply doesn't appear when ortho is on (it did in the past). If I switch off ortho, the tracking line will however appear - but then the line I am actually drawing is no longer pointing in direction 0, 90, 180 or 270 degrees  

Then it stands to reason it is a tracking line setting.  Have you checked?
Have you also posted your question in the Draftsight forum (at their website)?John Connor2017-03-15 11:25:02

I am unable to find any tracking line settings in Options.No, my inquiry has not yet been posted on any other forum than this.

I don't have access to my copy of Draftsight at the moment so I am unable to test the functionality of the features you have mentioned.

I managed to solve it Apparently, "Parallel" has to be unticked in Options -> User Preferences -> Drafting Options -> Pointer Control -> EntitySnaps. Still puzzled though how this box was unticked in the first place. Anyway, it works now.

Your perseverance is commendable.