The default for alt+right is to use code completion, it does the same as ctrl+space.
You can assign navigate forward to alt+right here:
Tools -> Options... -> Keyboard
Type "View.NavigateForward" under "Show commands containig" and assign alt+right to Text Editor. You can select the latter under "Use new shortcut in".
I've assigned alt+right to Text Editor but the menu item "View->Navigate Forward (Alt + Right Arrow)" becomes disabled forever regardless restarting IDE and committing Alt+Left many times.
Default Ctrl+Shift+- is still working in spite my settings. It works unstable sometimes but it's better than nothing :) Actually I didn't know this shortcut, thanks for it.