Cranky dock and flashy Youtube probs

Hi

Macbook Air

10.11

i7

4gb 

1. For a long time now my dock has been acting cranky.

By that I mean if I just head down to the dock where I know I am close to an app I want, usually the dock should rise up happily to meet the cursor.

As it is I often have to waggle the cursor around the area at the bottom or worse still often have to go to the bottom corner to activate the dock.

Enough's enough......this is a nuisance and needs fixing.

(I thought of ditching the dock and reloading but I believe it's now part of the system?

2. While I'm here .....

If I open Youtube.......not as part of a search for a particular item but just open youtube.......it starts flashing on and off, the whole page.

I cannot enter anything in a search and have to do a "fake search" get the page up then change the search terms.

Any help with these two items greatly appreciated.