okay okay here the process.
I don't work like that, but its to show the problem in being more detailled as possible. (and as i can :p )
Note that maybe i've totally misunderstood the way it works but...
Here the result i want :

Now the imported objects when starting the scene, both objects are align on ground :

I have to take the blue one and slice it where i want it to be with the
move tool :

As i want only the top of the object, i use the
move vertically tool to slice a part of the object into the ground to be hide :

The object isn't exactly where i want, so i use the
move tool again :

And now the problem. As you can see, if i had to use the
move tool again i lost the benefit of the
move vertically tool, (the hidden part into the ground is now visible) cause the
move tool move the object on all axis X,Y,Z in same time and have a kind of autoalign (the green bums) on other objects.
Of course, one of the solution is to fix the position with
move tool, before use the
move vertically tool..but its a fake solution..
The
transformation/align tool could be used for simple objects, but if you have complex modeling, it's hard to have the wanted alignment. Or i have some problem to use the move panel ? (maybe...)
What i suggest is to add a kind of
move++ tool by separated axis, reachable on move panel or directly on object, don't know :

In fact, it offer the possibility to have in same tool, the move all axis, the move vertically and add the move horizontally which is not possible for now (why one and no other?)
I don't know if its possible or not, i'm not telling that i know this kind of things better than you of course, its just a suggestion.
thanks for reading =)