Here is the link to the topic: https://forums.oracle.com/forums/message.jspa?messageID=10088724#10088724
The problem is that when you set a value of a page item on another page in a region button and the value has a space in it, the value on the receiving page replaces the space with %20.
To recreate you can do the following on a demo app at apex.oracle.com
Run the app and see the value displayed on page 4 as: "VAL%20WITH%20SPACE" Also see the url: http://apex.oracle.com/pls/apex/f?p=60043:4:1914750686915384::NO::P4_VAL:VAL%2520WITH%2520SPACE Instead of just %20 as it would normally say, now it says %2520.
- Go to page 4 and create a display only item called P4_VAL
- Go to page 3 and create a button redirects to page 4 and set the value of "P4_VAL" to: "VAL WITH SPACE"
This must be an error??
Also, if I change the url to: http://apex.oracle.com/pls/apex/f?p=60043:4:1914750686915384::NO::P4_VAL:VAL%20WITH%20SPACE It works correctly.
So it seems that where it goes wrong is in the javascript redirect code of the button (link generation)
Update:
This has been filed as a bug and is tracked with Oracle bug #12971989. It will be fixed in the first patchset for apex 4.1.
Thanks to Anthony Rayner for answering me.