How to include a file without having to make an extra "library" for this?

Is there any way to instruct the Arduino IDE preprocessor to not treat an #include as including a "library", but just to include the file?

The reason for this:

I want to keep the user interface resources together with the matching ".pde" project file.
If I keep them in one file together with the actual project code then the first 80, 90% of the sketch are only the user interface #defines.
As these aren't changed often after creating the screen/dialog layout, they only fill up the sketch with data that is no code.
So I need to separate that constant data into another file.

I do NOT want to have to create an extra "resource library" for each project's version, just to contain the user interface layout for one particular .pde version.
I want to keep this include together with the matching .pde in one directory.

So, is there any way to do this?

Check out the tab feature on the IDE.

If there are multiple .pde (and .cpp files?) files in the same directory, they will get concatenated with your main .pde file, and you can specifically include .h files with #includes with quotes.

#include "fileinsamedirectory.h"

Thank you WizenedEE for your answer.

The problem is that I always get an error message "No such file or directory", no matter whether including quoted or bracketed (arrowed), even if I supply a full absolute path to the file.

I also noticed that if in the sketch working directory are other .pde files, they get opened in tabs. The bad thing about that is that simple file catenation doesn't do what I need. I need to be able to determine at what point what file(s) get included. So the multiple tabs don't actually help me.
Using a different filename extension also didn't help.

So these things didn't work out.

Maybe there is some way of telling the preprocessor that a particular file #include is not to be interpreted as a "library" inclusion, but as a normal file inclusion in the way it is usual outside the Arduino world?

After reading the post,84663.0.html I finally found out that I had to restart Arduino to make it compile...
This solved the problem. Thanks again!