Legacy chat I believe had a bug relating to the sizing. Basically, when opening roblox, the size of the game window is not what it should be (it’s instead somewhat small for a short period of time). Depending on when the chat loads, it registers a size that isn’t the actual size of your screen, and would sometimes wrongly set the chat size has Tablet or Phone
This is how it detects the device type internally
(Settings module)
This is something I have fixed in my forked version of the legacy chat (however, I cannot tell you if the size settings in my forked version are the same as the default ones)
It’s possible that this bug doesn’t occur when in studio, since the game window doesn’t resize when play testing
The default size for Desktop has a scale of 0.3