When redesigning the grid layout and handles, commit [1] removed the filter that allowed the grid to be clearly visible on dark backgrounds (added in commit [2]). Without this, the background grid when dragging/ resizing and the highlight effect when changing the gaps are difficult to see. This commit adds this filter back, but with a lowered opacity in order to not obstruct the view too much. [1]: https://github.com/odoo/odoo/commit/70f723a9f78c406746f5409f6a89cbe93ad21580 [2]: https://github.com/odoo/odoo/commit/1aa81243b7c80069c576381e2f3b04281455794f task-3369695 Part-of: odoo/odoo#136683