As part of the Proton design overhaul, Mozilla plans to remove the compact panel display mode from the interface settings (the hamburger menu in the panel -> Customize -> Density -> Compact), leaving only the normal mode and the mode for touch screens. Compact mode uses smaller buttons and removes extra space around panel items and the tab area to free up more vertical space for content.
The reason cited is the desire to simplify the interface and offer a design that would suit most users. It is noted that the compact mode switch is quite difficult to find in the settings and, according to the developers, few people use this mode (when analyzing telemetry, the developers lose sight of the fact that people who change the default settings turn off telemetry transmission more actively and fall out of statistics).
According to Mozilla, 93.3% of users use screens with a vertical resolution of 768 pixels or higher, so it was decided to use 768 pixels as the minimum height for optimization - 92 pixels will be allocated for the tab bar and address bar (in the new design, the bar will become thinner than it is now in normal mode). With the classic menu disabled, 88% of the vertical space will be given to content, excluding operating system panels and not considering that some users do not maximize the window to full screen. Considering the vogue of modern sites to pin headers and display a dialog at the bottom with a warning about the use of cookies, which you can only accept, but not refuse, navigation on laptops with small widescreens resembles the view from the embrasure.
Source: opennet.ru