how to restart level without going back to main menu??

[Zένø™ 👌]

clearing doesnt clear anything!

[[WRG] McKay]

Clear(the button on the bottom left corner) will delete every drawn plaform, however this is just there for convienence, it's exactly the same as what you would do by right clicking manually on each platform - and the same rules apply here, you can only use the Clear function when the fluids are inactive(when the simulation is off). So this isn't a "restart level" button.

Every time you press the space bar the level(simulation) (re)starts\stops, so basically restarting is done by pressing the space bar twice.