I am an indoor mango grower from Finland. I pruned my mango tree after the first flush at 28cm height. I just cut the growing tip off. I got three new tips, but only one of them grew and even that was only about 2cm and only 2 leaves so far. The other two tips seem to be drying out, there is only few of the little leaves left on each one. Does it need more light, warmth, water or what? Edit: This was supposed to be a reply to "do I prune my indoor mango tree?"
It is the natural response of a plant that 'wants' to be a tree with a single trunk - the lead shoot (in this case the first replacement after pruning) produces auxins which suppress the growth of the lower buds. If all the side shoots grew, the tree would end up with a forked trunk which is weak, liable to split, and thus an evolutionary dead-end.