command F

I have a concerning the command F function, in particular regarding its for a PDF file in preview. Normally when I used this function, I was able to see the results as I started typing and I could edit my search while going through the document. I still can on safari (the format of the function remained the same there), but this is not possible anymore for a PDF file in preview. The search box has also changed place and is now in de middle of my screen. Does anyone know how I can change it back to the way it was?

Thanks in advance,

Jimp