So in any application I use that has a "Choose a File" (or similar) dialog, it's always the same one (excluding small java apps that use Swing's builtin File Manager and similar situations). It's been a year or two since I've dealt with "file choosers" but it was with Java, and I just remember being able to set the look and feel to "Native" or whatever and it would use Windows' native file chooser.
In Linux, which application provides the file chooser to applications? I always that it was the default file manager but that doesn't seem to be the case as far as I can tell. I'm using Thunar as my file manager in XFCE but the shortcuts I have in my side pane in Thunar don't match those that are in the shortcuts side pane of the file chooser which is what leads me to believe another application/library provides the file chooser functionality.
What I mean:
My shortcuts in the file chooser (I deleted most of them to show that they aren't the same ones kept in Thunar):
My shortcuts in Thunar:
What software provides the file chooser for applications? The widget toolkit (GTK, Qt, etc.) (Thanks Ignacio!) Is it the graphical toolkit that the applicatoin is using (GTK, Qt, etc.) that provides it, perhaps? Yes
If so, how can I make it use my Thunar shortcuts if at all possible?