Construction line ending

Hello
Step by stem I’m trying to get familiar with the basic concetp to use Sketchup
But there is still many behaviour that I do not really understand / control
For example Why when I’m creating a construction line, sometime it goes to infinite, sometime it stop to the point I’ve released the mouse button ?
Why ?

Drawn from an axis or from an edge will give you an infinite guide parallel to the source you used
Drawn from an endpoint or an intersection of two guides or from the intersection of one guide and an edge or face will result in a guidepoint. The dashed line of a guide can be used as an inference.
The one attached to the guidepoint can’t be used itself, only the guidepoint itself.

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