[macOS] Custom cursors larger than 32 DIP revert to default when intersecting browser edges

[李 维]

Dear Chromium Team,

I am writing to report an issue I encountered while developing a Chromium-based game on macOS. When I use a custom cursor with dimensions larger than 32 DIP, if the cursor’s outline intersects with the bottom or right edge of the browser window, it reverts to the default system cursor.

I understand the security motivation behind this decision—particularly to prevent abusive practices such as obscuring important browser UI elements [see https://chromestatus.com/feature/5825971391299584]. However, this change has unintended side effects for certain game applications. In our use case, we require a full-screen gaming experience, where custom cursors are critical to immersion and maintaining the game’s artistic style. The restriction causes the cursor to suddenly change when touching browser boundaries, which is especially noticeable on macOS since the default system cursor is relatively small, making the disappearance of the custom cursor feel abrupt and disruptive to the player’s immersion.

I sincerely suggest reconsidering this policy in trusted contexts. For example, Chromium could provide an API that allows developers, when necessary, to permit custom cursors to remain visible even when intersecting the bottom or right browser edge.

Thank you for considering this feedback. We greatly appreciate the balance you maintain between security and usability, and we hope a solution can be found that meets both safety requirements and user experience needs.

Sincerely,

lw404