1490304 - Cursor jumps to wrong horizontal position when pressing up/down after setting selection through Selection API

Status: NEW

(Core :: DOM: Editor, defect, P3)

Description

[stef.busking]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.81 Safari/537.36

Steps to reproduce:

Reproducible example at https://codepen.io/Bwrrp/pen/PdRZzx

The example contains two paragraphs in a content-editable div. Place the cursor in the first paragraph and press the right arrow a number of times to move a good distance horizontally. Then press the down arrow to move the cursor down. Now do the same to go left, then up.


Actual results:

After moving down as expected, the second and any further attempts to move vertically using up/down seem to ignore any horizontal movement performed by going left or right since the last vertical movement.

Note that the left and right arrow keys move the cursor using JavaScript and the Selection API. Moving up and down uses the native behavior. It seems that the horizontal position used for moving to the next / previous line is not updated correctly when JS is used to move the cursor, and any vertical movement afterwards is based on an older position. Pressing up/down or clicking anywhere to place the cursor does update this horizontal position, so the next vertical movement behaves as expected.


Expected results:

Expected vertical cursor movement to always move to a position above / below the previous cursor position, even if that previous position was set using the Selection API.

Comment 1

[Stefan [:StefanG_QA]]

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0 (20180913100107)

I have tested this report on Windows 10 and Ubuntu 18.04 using the latest Nightly, Beta and Fx release builds. I was able to reproduce the mentioned behavior using the provided codepen page. After moving down as expected, the second and any further attempts to move vertically using up/down seem to ignore any horizontal movement performed by going left or right since the last vertical movement.

Please change if this is not the correct component!