Moving page down, or up. doesn't always work

Not sure what the line on the right of a page is called. It is used to move a page up or down when reading an article. It works fine on the Mac Forums page, and sometimes on other pages, but when reading news articles on my.yahoo home page many times it does not work. I recently gave in and upgraded to OS Sierra and am not sure if this is the cause. I do use a wired mouse to move my cursor. Any ideas?

Most people call that line a "scrollbar".. Anyway, with websites, a lot of them use variable boxes with fixed and variable length. So some parts of the website are fixed height to the size of your browser window while other parts are longer and will scroll. So it is important to move your mouse around and find the scrollable part..

Your mouse shouldn't matter..

A screen shot of such a web page with the inoperable scroll bar indicated might be useful. (Beyond my skill set, but if you can...)

It's not that it is inoperable, it's that it's erratic and not synced to my movement. For instance if I scroll down... nothing happens for a few seconds... then the the scroll bar will jump down. It is not s smooth transition. This most recently happened on a page of The Washington Post There is a delay of a few seconds, the the scroll bar jumps lower.
On another question: Is there a way to widen the scroll bar? My wife, who uses windows like the wider scroll bar better...as do i. I never had a problem like I have with my iMac.
One last thing...which may be related to my other questions...when I go to a web page article and start to read, it jumps around about 2-4 times before it settles down in one place where I can read without further page movement. Not sure why that happens.
Thanks Pete

What version of OS X are you running and what browser? The scrolling should be very smooth and should track the page VERY accurately. It should not jump randomly. A few versions back in OS X the scrollbar went from being always being visible to only visible when scrolling like in iOS.

You can however change that by going to System Preferences->General and you'll see the scroll bar options there, set it to Always to make it appear all the time. The normal scroll bar is thinner, but if you hover over it, it will become thicker.

One last thing...which may be related to my other questions...when I go to a web page article and start to read, it jumps around about 2-4 times before it settles down in one place where I can read without further page movement. Not sure why that happens.

Click to expand...

I've seen that. It's caused mostly by the ad at the top of the page changing size multiple times before it settles down. If you are a bit down the page, you don't see the ad change, but you do see the text reacting to the change in the ad size. I use ghostery to block all the ads now and the jumping has stopped.

Thanks all. I think Jake nailed it. Sorry for the delayed response