It looks like you've essentially implemented a 6DOF control scheme; with a 6DOF control scheme, cumulative yaw and pitch can indeed result in perceived roll.

It sounds like you want 'from scratch' Euler or spherical angles instead. In other words, represent the orientation using two angles (e.g. pitch and yaw), and build an orientation matrix from them 'from scratch' each update.

i think

"D3DXMatrixRotationAxis(&RotationAroundLook, &Look, DeltaRoll);"

If thats been calculated in your mouse's view change code then its possible that it is where you've come unstuck...

I'm not sure on your naming convention but...

I'm expecting 'rotation around look' is a reference to a target vector,
'rotation around up', is a reference to the 'up' vector or Y plane,
and 'rotation around right' is a reverence to the horizontal or X plane.

Your use of deltaroll against look, also reads to me that you have a roll around the target which would result in a movement in a circle on the Z,Y plane, not the X,Y plane.
ZY movement with a target point defined will cause the camera to roll with the target in the middle, kind of like an airplane doing a barrel roll.
XY movement with a defined target will cause the camera to rotate around the target much like a bucket on a string rotates around you when you spin it around you.