System Information
Operating system: Win10 64 bit
Graphics card: GTX1070

Blender Version
Broken: 2.80, 3dc9da3a74ee), 2.79
Worked: N/A

Short description of error
Loop cut and slide with tweak action on right mouse gets canceled in same mouse click when using left mouse select. So basically I would like to invoke an operator (loop cut and slide) with a right mouse tweak action, then release the mouse button with the operator still running, then confirm with the left mouse button.

The problem is that the operator gets canceled with the same mouse click that invoked it when the right mouse button is released which seems like a bug to me.

With a tweak action it's impossible to confirm at all with the mouse (press tweak action, hold it and move the mouse to make a loop, left click, nothing happens) which seems like another bug. With a press action on the right mouse button the same cancellation behavior is still there but it is possible to confirm the operator with left click. The click action works the best because it's not canceled after letting go of the right mouse button.

While right click is the cancel operator I think it should only cancel when the invoked operator has had its hotkey released once, even if it's a mouse click. For example, try holding the grab hotkey and clicking right mouse with left mouse select. In my opinion this shouldn't happen, the grab key should have to be released once first.

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
(from startup blend)

1. Add a cube if there isn't one.
2. In the keymap, set loop cut to right mouse tweak south.
3. Set input to left select.
4. Enter edit mode.
5. Move mouse down and press right mouse (for tweak action) to invoke loop cut, then release it.

Result: Operator is cancelled when the invoking hotkey is released.
Expected: Operator doesn't cancel and you can move the mouse around with operator still running even after letting go of invoking hotkey once.

6. Change loop cut to middle mouse tweak south.
7. Move mouse down and press middle mouse (for tweak action) to invoke loop cut, then release it.

Result: Operator doesn't cancel and you can move the mouse around with operator still running even after letting go of invoking hotkey once.