It isn't just you. I usually end up shrinking the size so it's no longer visible. It beats fiddling with it until I can get a halfway decent location.

Yep Checked that....its enabled.  The it just doesn't give you the option of placing active components anywhere. as you can see after selecting the weapon I want there are not hardpoints to attach it to and hitting place just randomly plops it on the ship where ever. 

Thanks Old-Spider that is extremely helpful.

Thank you dude........I've got to say this is the most convoluted and stupid designer they could have possibly created.  I wish they would scrap the whole thing and go back to how gc III was.  That was intuitive and easy to use and your ships were available immediately after designing them.  Now I've got to figure out how to get ships to show up in the list to build as I have multiple designs all tweaked out and the only things that show up are the default vessels.  Theres no point in even having a designer if you can't build the ships you design.

The ship designer is generally broken and I hate it, but I wanted to mention: I get an issue where I can no longer put parts on hardpoints.  But I found that if I double click a part (to just add it wherever the game wants to put it) and then remove it, I can then add parts manually again.  This works until I have too many parts and the designer doesn't let me see the newest ones because it's terrible.

It sounds like the initial problem was that the red hardpoint markers weren't visible for OP.  I thought at first he had the issue that I did, but even though my issue is different, I felt like it was similar enough to mention.

This issue takes place outside of "cosmetic mode", where you place weapons and functional parts.  That's where a) sometimes it stops letting me put parts on until I do the workaround I mentioned above and b ) there's a very limited non-scrollable window to show all your functional parts.  If you have too many to list there, you just can't see them.

HOWEVER!  The designer is less buggy in the latest update!  I can actually scroll to the bottom of the ship list (which is still cluttered with scores of wacky space station designs for some reason) to see my actual ships.  This is the first time in months that this has worked.  Huge thanks for this.

The designer still grabs a ship hull from a totally random ship set, not from my civ's ship set, which is bizarre to me.  And can I also suggest that the ships that automatically have their primary functional part allocated -- colony ships, constructors, etc -- that the part at least shows up in the parts list?  Maybe pin it somehow so it can't be removed from the ship, but at least indicate that it's there.