I'm trying to play Constructor. The problem is every time when I'm pressing control + some function key (for example: F1) DosBox is reacting instead of game. How to disable all DosBox internal shortcuts? I do not need them, I just want to play the game :D

Nevermind, misread something.

Does this help?

http://www.dosbox.com/wiki/Mapper

I found this help also, but, as far as I understand, it is for binding new keys for dos game and I would like to disable DosBox shortcuts - that is quite different.

It doesn't appear to be exactly what you asked for but I thought it still might be a suitable fix. Nevermind me then, I don't know how to disable DOSBox shortcuts. I suppose, since it is open source, you could edit the shortcuts prior to building it yourself. ;-p

Yay, I found the answer here: http://vogons.zetafleet.com/viewtopic.php?t=26528

By looking at this long readme, I found it is indeed needed to modifying the mapper file. I've added Alt key to every original Ctrl-Fx shortcut :D So it is now Alt-Ctrl-F1 instead of Ctrl-F1. :)