When holding left mouse button and pressing right mouse button, then releasing the left button, mouse cursor is stuck at the Flythrough mode.

To reproduce:
1.Create new project
2.Open scene view
3.Hold left mouse button
4.Press and hold right mouse button (now holding both mouse buttons)
5.Release the left mouse button
6.Release the right mouse button
7.Observe as the mouse cursor is the Flythrough modes cursor.

Reproduced on: 5.3.6f1 5.4.3f1 5.5.2f1 2017.1.0a2

Notes: when mouse is in Flythrough mode, you cannot select any other transform tool. In 5.6.0b10 and 2017.1.0a2 when the cursor is stuck you can simply move the cursor while no button is pressed and the cursor becomes normal. Its stays in the Flythrough mode while the cursor is moving though.

Workaround: just press anywhere with any of the mouse buttons, and the cursor becomes normal.

Win 10 Pro