BusyIndicator breaks from settings running to false, then to true

Description

Setting running to false, then to true during same cycle of event loop leaves BusyIndicator with a property value of true, but visually hides it like if it's not running. The problem is especially evident is indicator is bound to a timer, because Timer::restart() method toggles its running property twice: OFF and back ON.

Steps to reproduce:

1. Create BusyIndicator component
2. Create Timer
3. Bind BusyIndicator's running property to the timer's one.
4. Run the timer.
5. While it is running, restart it (e.g. using a button it the interface, or another timer).

Or just open the attached project, and play with buttons there.

Expected behavior:

BusyIndicator should visually be running when it's ON.

Actual behavior:

BusyIndicator is not visible.