1. if some apps misbehave when ctrl+space is used by the xkb layout they should be fixed by their upstream. xkb layouts are a fact of life which means apps have to deal with them gracefully
2. plus with multimedia keyboards so common nowadays almost every home keyboard will have a dedicated start/pause key, so trying to grab ctrl+space is not necessary
3. in the meanwhile you're free to try the other nbsp options. I made this key configurable for a reason — none of the options work well in every case so users are free to chose their lesser evil. When the other default were set other people complained for other reasons
I don't have any magic solution:
1. if some apps misbehave when ctrl+space is used by the xkb layout they should be fixed by their upstream. xkb layouts are a fact of life which means apps have to deal with them gracefully
2. plus with multimedia keyboards so common nowadays almost every home keyboard will have a dedicated start/pause key, so trying to grab ctrl+space is not necessary
3. in the meanwhile you're free to try the other nbsp options. I made this key configurable for a reason — none of the options work well in every case so users are free to chose their lesser evil. When the other default were set other people complained for other reasons