Translation:
Who can explain to me why this entity does not remain solid? To check I use the wired mode, I create my component and I save it. Do I have to lock it while waiting for me to finish all the entities? The unstable nature of SketchUp is annoying and unacceptable. It causes a huge waste of time.
What entity are you referring to, there are many in the mode. A group or a component remains solid until you edit it and draw something that makes it a non-solid.
If you mean this, @ateliernab showed you to to avoid it in another post.
Maybe you should learn SketchUp instead of criticizing it, I also recommend youto read more posts and you will see that people do real wonders with it.