I create an object in blender and when I hit S to scale etc the object scales madly with the mouse movement. Same goes with rotate and other transform options. The 3D widget simply changes to a circle, not the normal symbols. I've reset the interface and even did a reinstall, but makes no difference. Its make blender unusable because you try to transform something by a a few degrees or scale and it does what ever it wants. ANY IDEAS or is this just a bug. I noticed it only started doing this with the 2.78 update. I also noticed that panels have move around as well but thats another story.
It matters where your mouse is relative to the pivot center before you start the scale. If you start far away from it, it will scale slowly, but if you start very close to it, it will scale madly.
You can change the pivot point in the 3D-Editor->Header->Pivot Point
And the 3-D Manipulator widget can also be changed from translate/rotate/scale.
You can switch the rotation mode from the regular to trackball rotation simply by hitting r a second time.