System Information
Operating system: Win 10 64 bit
Graphics card: 1050ti
Blender Version
Broken: 2.8-e7a0f0a9934e (2.7x Keymap)
Worked 2.79b
Exact steps for others to reproduce the error
Try to CTRL-Tweak-Left in object/edit mode (hold ctrl, click left mouse button and hold it too, then start dragging mouse). It activates box selection instead of lasso