Selection rectangle is not aligned with horizontal and vertical axes anymore in Illustrator

Question

I was wishing to resize my triangled shape horizontally, but suddenly found it is not aligned anymore:

If I resize it, it obviously resizes not horizontally.

How did I do this :) and how to exist this state?

Answer 1

This is the "Bounding Box" and can be shown or hid by going to View> Show/Hide Bounding Box.

In your example you can go to Object> Transform> Reset Bounding Box which will re-orient your bounding box sides to be horizontal/ vertical to your artboard. This would allow you to resize your object horizontally (relative to the Artbord).