When dragging a material over a surface in the scene view, the undo stack is spammed with undo states

[nukeandbeans]

Bug is located here:

realtime-CSG-for-unity/Plugins/Editor/Scripts/View/DragAndDrop/SceneDragTool.Materials.cs

Line 564 in a3ccdb6

if (!modified)

Where the check is inverted from what it should be.

(!modified)
{
    // etc...
}

should be

(modified)
{
    // etc...
}

This will be fixed with other fixes in PR #349

[Janooba]

Confirmed fixed in #349 using 2019.4.31f1