I solved this problem by going to main menu Edit > Preferences > Keymap then 3D View section and on the right was an option to Reset and it fixed the problem.
Now I can choose objects back in Object Mode as usual.
I've been dealing with this problem in 2.8 and having no luck finding fixes online. But I've just found a fix, so I hope this comment might help someone in the same position. Have a look at a plugin named "Fast Carve". It has a great set of tools similar to Adobe Illustrator's Pathfinder tools. Including a Union button.
Use this to join your 2 objects ...
The selection method you describe is now implemented in Blender 2.81, together with Ctrl-left-click selecting (Cmd on a Mac), to toggle between Active and Unselected states for individual items.
B Box selection is also available, as in the viewport: left-drag to select, middle-drag to deselect.
In Face select mode you can select areas bounded by seams.
At some time or another you are probably going to have to UV unwrap your models to add "image" textures so why not start now :)
Once the seams have been added then you can select individual areas bounded by seams with the L key. see screenshots below
Looking at the geometry, you'd be able to use Loop Select.
You can do this by holding Shift+Alt and clicking LMB to select. Holding Shift tells blender to not clear the previous selection, and Alt enables Loop Select.
Things to note: if you click near the top/bottom of one of the faces, Blender will Loop Select in the vertical direction. Clicking on the ...
This should be rather easy, if I didn't miss anything.
Select and delete all
Filter name through the search bar.
Press Enter to confirm the search.
Select all, shortcut A
RMB > Delete
Deleting the whole hierarchy of empties for some reason doesn't work well in the outliner.
Just move your mouse over to the 3D viewport and it works well.
Flushing select mode.
Recommend naming a bmesh representation of a mesh bm and reserve mesh or me for a mesh.
bpy.ops.mesh operators manipulate the mesh. A bound bmesh, ie from_edit_mesh is still not the mesh. An edit mode mesh is what we don't have a handle on via python. Can set me.vertices properties in edit mode, but will have no effect on the "...
This might work for you, depending on your topology:
Select 2 edges at the right interval
CtrlShiftNumpad + (repeatedly), expand the selection at the same interval.
Header > Select menu, Select Loops > Edge Loops
You've pressed W. This is mapped to the selection tool and will cycle through the different selection methods if the select tool is already highlighted.
Either press W until you're back to box select, or click and hold the Selection button in the toolbar below.
Available selection methods:
The answer of @ObscureGuy was correct, but just to make sure: You can only select mesh parts in Edit Mode, not objects. You can select every part of an object's mesh/data, but technically you cannot select objects.
Ok after some more playing I found it. Any of the icons with the arrow in the corner you can left click and hold to bring up a sub menu.
Also using the keyboard shortcut for box select will change the icon to that again.