Closes https://github.com/zed-industries/zed/issues/26009 https://github.com/zed-industries/zed/blob/21484a2e9d07b6285f112ba49ca413cdb8e360e4/crates/gpui/src/platform/linux/platform.rs#L517-L519 `with_common` panicked at `borrow_mut` which is the way it's implemented for X11, Wayland and Headless Linux counterparts. https://github.com/zed-industries/zed/blob/21484a2e9d07b6285f112ba49ca413cdb8e360e4/crates/gpui/src/platform/linux/wayland/client.rs#L722-L724 By accessing the appearance global instead of a `RefCell` with it, the panic goes away with one notable side-effect, on Linux only: the first global's value on `Dark` appearance would be `Light`: it becomes normal instantly, thanks to https://github.com/zed-industries/zed/blob/21484a2e9d07b6285f112ba49ca413cdb8e360e4/crates/workspace/src/workspace.rs#L1083-L1090 Things work without flickering: [linux_theme_toggle.webm](https://github.com/user-attachments/assets/0e39ddc0-b4ff-4475-93ff-7b2bd7233628) Release Notes: - Fixed a panic on Linux theme appearance change