Arduino IDE uses 'old'/cached version of libraries

Hello,
For my two-wheeled robot I’d like to use a sonar and an IR-remote. Hence, I’d like to include two libraries, like this

#include <NewPing.h>
#include <IRremote.h>

I recieved an error:
IRremote\IRremote.cpp.o: In function __vector_7':* *C:\Arduino\arduino-1.0.1\libraries\IRremote/IRremote.cpp:311: multiple definition of __vector_7’
Sonar\NewPing.cpp.o:C:\Arduino\arduino-1.0.1\libraries\Sonar/NewPing.cpp:214: first defined here
which is because both libraries use the same interrupt code/system/thing.

After searching the forums, I found this topic:
http://forum.arduino.cc/index.php/topic,126251.0.html
which basically explains how to modify the NewPing library. I have followed the instructions.

The problem is, and I have experienced this before, is that the Arduino IDE somehow uses an old version of the library. I could change the content of NewPing.pde to $@##@something@@ and it still wouldn’t change the behaviour.

(as a side note, this is also why my contributed libraries now look like this:
ultrasonic1
ultrasonic2
ultrasonic3
ultrasonic4
NewPing
in an attempt to bypass this problem)

What is causing this problem and how can I fix it? I think it is probably some caching isue. Thanks for any help!

Jumboman:
I could change the content of NewPing.pde to $@##@something@@ and it still wouldn’t change the behaviour.

What file is this?

If you want to find out whether a file you’re looking at is actually being used, temporarily rename it and try building again. If the build still succeeds then presumably it is using some other copy, and you could carry out a file system search to find that other copy.

There was an issue with earlier versions of the IDE about temporary files not being renamed/deleted. Try updating to 1.0.5.

PeterH:

Jumboman:
I could change the content of NewPing.pde to $@##@something@@ and it still wouldn't change the behaviour.

What file is this?

sorry, I meant NewPing.ccp of course. I've renamed the files in the library and it doesn't affect my sketch (that is, I still get the same error) so it must have cached it somewhere. I've searched my system and it turns out that when I add a library from the documents/arduino/libraries folder, it makes a copy of it to the workspace/libraries folder. I've edited this one and now it works fine. thanks for your suggestions!

you must restart IDE after (almost) every action on libraries (adding/deleting/renaming/..)

Did you do that?