How are you setting selection? The anchor and focus objects come as a result of DOM selection. In chrome.automation, there are two ways to trigger a selection action:
- chrome.automation.setDocumentSelection
- on an AutomationNode, call setSelection

I'm clicking and dragging with the mouse. More nodes are highlighted visually when I click and drag than are coming through on the automation tree, on this page in particular.

Clarifying title. This is information we get from Blink, so the bug is almost certainly there.

+ nektar, who was the last one who was looking at Blink selections in detail.

I've got another two example of the same type of bug:

-------------------------Second example------------------------------

Click and drag with the mouse to select everything on the chrome://settings page, starting at the Network header. Only the Network header node appears to be selected in the Automation tree.

focusedNode acquired from chrome.automation.getFocus:

focusedNode.root.anchorObject.name
"Network"

focusedNode.root.focusObject.name
"Network"

focusedNode.root.anchorOffset
0

focusedNode.root.focusOffset
7

Expected result: the focusedNode is different from the anchorNode, and is "Open a specific page or set of pages" or something further down the page where highlighting stopped.


-------------------------Third example------------------------------
Click and drag to select text in chrome://settings, starting at "Ethernet", through "Add connection".

focusedNode acquired from chrome.automation.getFocus:

focusedNode.root.anchorObject === focusedNode.root.focusObject
focusedNode.root.anchorOffset === focusedNode.root.focusOffset

Expected:
The offsets and focus/anchor objects are not exactly the same, since a portion of the page is selected.