mouse select not working on a diagram

Using
librecad 2.1.2
Ubuntu 18.04
AMD FX chip

Why did I loose the ability to select an object with a mouse click?

Imported a block of objects into a diagram and then the mouse cursor could not select an entity anymore.
Exploded the block.
Still will not select objects.
It will select the object with a window.
Tried any object and same throughout diagram and many layers.
Also strange behaviour with clicks. Clicking then changes the cursor to the one associated with choosing a reference point. Clicking again changes it back to the arrow. It does not matter where I click. It can be in empty space, away from any object.

Closed and restated the program. No change.
Closed program and rebooted computer. No change.
Other diagrams work properly.

without single object click select, I cannot do TRIM and some other functions.

Solved.

The dimensions that were imported with the block caused the problem.
So: do not import dimensions with a block.