I am trying to convert a simple shape into a symbol.
When I do that, the selection box (I don’t know the technical term for it) changes.
I need to keep snap to grid on because i need precision in my work. The changes in how illustrator sees this symbol really makes it tough because snap to grid is on. Now when I move this symbol, the selection box aligns the outside of the symbol to the grid.
I need help to understand how I can keep the symbol and the selection just like in the first figure.
Plus.. what is the technical name for the pink selection box?
Firstly, the pink box is commonly referred to as a bounding box.
Secondly, I don’t think that it is possible to achieve the behaviour that you are looking for.
In your first image the bounding box shows the extent of the shape. The key line is a style applied to that shape so it can go beyond the bounding box. Once the shape is converted to a symbol, the appearance is expanded (sort off) so the bounding box moves to the extent of the resulting object. That’s just how illustrator works.
As I see it, you have two options; either don’t use symbols (you can still duplicate the shape and it will then behave as you want it to) or if you need to use symbols, then align the centre of the symbol to your grid, rather than the edges. If your example is representative then the centre won’t move.