I come from Windows background and it's very furstrating that when I start typing something, I can't use arrows, backspace, alt+arrows etc. anymore thanks to this little box in the right bottom corner:
Is there any way at all to disable it and make it behave like Windows Explorer?
That search box is part of the GTK windowing system and I don't believe it can be changed in Thunar. Thunar is still GTK2 based I believe. GTK3 file choose widgets do have a more Windows-like search feature, which may have made it into Gnome3/GTK3 based file managers.
Thunar is open source, so you could modify it to include an option to disable search in the TreeView used for file listing and submit a patch/pull request.
You can also just press escape to close the search box and keyboard navigation is restored.
