12020-02-11 Wenson Hsieh <wenson_hsieh@apple.com>
2
3 macCatalyst: Unable to grab scrollbar on editable text field
4 https://bugs.webkit.org/show_bug.cgi?id=207615
5 <rdar://problem/59212993>
6
7 Reviewed by NOBODY (OOPS!).
8
9 In macCatalyst, hovering over the scrollbar (an instance of the internal UIKit class
10 `_UIScrollViewScrollIndicator`) is required in order for a click and drag with the mouse to actually move the
11 scrollbar. This is because UIKit depends on the cursor interaction added to this view to recognize and call its
12 delegate methods.
13
14 However, we override hit-testing in WebKit to skip over all children of scroll views, and instead force hit-
15 testing to find the scroll view instead. This means that UIKit can never hit-test to the scroll indicator views
16 embedded directly beneath each WKChildScrollView, so the cursor interactions described earlier will not
17 recognize. To work around this, special case these scroll indicator views, such that we will allow
18 -hitTest:withEvent: to find these views.
19
20 * UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:
21 (-[UIView _web_findDescendantViewAtPoint:withEvent:]):
22