midi problem

i have a midi controller that I want to use on my rekordbox, but it seems like rekordbox only recognises the buttons in "learn" mode

I have a Akai LPD8 MKII and want to use it next to my Pioneer XP2 to control some fx buttons and track sepparation

When i open the midi control pannel, select the LPD8 MKII, add the functions I want en then push learn and the prefered button on the controller, it gets connected. If I do this when a song is playing, I even hear the function work, but as soon as I close the midi control pannel, my rekordbox does not respond anymore to the buttons.

anyone an idea what the problem could be?