Is canvas: it 3 the mousemove event. mousedown, mouseup
Inside the canvas are buttons.
I want these buttons to move in the type of drag&drop
when I'm just driving the mouse, the mousemove event is invoked
but if I push the button and drive on canvas mousemove is not called until I call the mouseup event
How to fix and why is this behavior?
All right, so it should work, this is a standard interaction components, not only in WPF.
After a mousedown on the button the mouse is considered to be owned by this object, so the rest of the UI it is not responsive.
For your specific task under drug-drop is a Drag event Over - reaction to holding the mouse button pull the object drug over another object (with the exception of the situation described above). Usually, the reaction is done so the user knows where you can "dropnode" object and where it is impossible, but it can be used in other cases.