synchronize two NSScrollView

Question

I read the document Synchronizing Scroll Views, and did exactly as the document, but there is an isssue.

I want to synchronize a NSTableView and a NSTextView. first let NSTableView monitor NSTextView, and everything is ok when I scroll the TextView, but when I try to scroll TableView, I found that the TableView will jump to another place(maybe backward several rows) at first, then continue to scroll from that place.

This issue still exists even after I let TextView monitor TableView.

anyone know what's the problem? can't I synchronize a TableView and a TextView?

Edited: OK, now I found that the TableView will go back to the place since last scrolling. for example, TableView's top row is 10th row, then I scroll TextView, now TableView's top row is 20th row, and if I scroll TableView again, the TableView will go back to 10th row first, then start to scroll.

Answer 1

I just ran into this exact problem while troubleshooting a very similar situation (on Lion). I noticed that this only occurs when the scrollers are hidden -- but I verified that they still exist in the nib, and are still instantiated correctly.

I even made sure to call -[NSScrollView reflectScrolledClipView:], but it didn't make a difference. It really seems like this is a bug in NSScrollView.

Anyway, I was able to work around the issue by creating a custom scroller class. All I had to do was override the following class methods:

+ (BOOL)isCompatibleWithOverlayScrollers
{
    // Let this scroller sit on top of the content view, rather than next to it.
    return YES;
}

- (void)setHidden:(BOOL)flag
{
    // Ugly hack: make sure we are always hidden.
    [super setHidden:YES];
}

Then, I allowed the scrollers to be "visible" in Interface Builder. Since they hide themselves, however, they do no appear onscreen and they can't be clicked by the user. It's surprising that the IB setting and the hidden property are not equivalent, but it seems clear from the behavior that they are not.

This isn't the best solution, but it's the simplest workaround I've come up with (so far).