Should this window gap be sealed and how?

[carnoob123]

Hello folks,
I have attached a photo of my window which seems to have a gap between the cill and the window (I am referring to the bit where that small leaf seems to be stuck).

Should this be sealed because I read somewhere that a gap is required for drainage but then I have also read that it can be sealed with silicone so rather confused....

 

[crank39]

No do not seal it, hidden under the gap are drainage slots

If you seal up then water(marked in blue) can't escape and will track back(red)