As standard Midi-option, I want to use all midi-sources, channel 1.
Every time, I change a midi-source, the setting changes to a midi-source, I do not want to.
Is it possible to "freeze" the midi-source option, so it does not change?
If this is not possible... Is it possible to change all midi-sources simultaneously in the option I prefer?
 
(I use Sonar X1 Studio)

X1 is not on my current machine but I am pretty sure you can quick group the Instrument and MIDI track and change the input settings all at one by selecting the tracks and while hold down the CTRL key select the input on one of the selected track.
 
Another option is creating a track template. Templates recall input settings.

Hello! The advice with selecting all the tracks is great. I tried it before, but did not hold the CTRL key while selecting the input.
So, it did only influence one track. Now, it works.
 
But it is a little strange that Sonar X1 changes the Midi-input-settings, every time I open the program. It should be possible to keep the settings in an easier way or choose a preference.

There is the possibility to save a midi-input preferred as "preset".
I did it, and afterwards, the settings did not change any more.