This patch is an alternative to D2806. Instead of increasing the size of the right selection panel to have an additional row, this patch reduces the size of the icons (from 40 to 32 pixels), to be able to display more entities (4 × 10 = 40 instead of 3 × 8 = 24).
The advantage is that this allows for future additions and mods, while not taking up more space, which is especially important on low resolution screens.
The disadvantage is that due to their smaller sizes, the icons become slightly harder to identify, especially on high resolution screens.
How it looks in game: {F1469891}
Related: D2051.
[EDIT] Further changes for consistency and visual harmony:
* Mini-map gets exactly the same height as middle selection panel.
* Selection group, technology research progress, and barter and trade resource icons are all standardized to 32×32 pixels too.
* Icons in left selection panel are shrunk to 32×32 pixels too.
* Left selection panel supports up to 15 formation types.
* Left selection panel supports up to 5 resource types.
* Left, middle, and right selection panels have the same margin between the icons and panel border.
* Command icons (middle panel) have their centre vertically aligned with the bottom row of the left and right selection panels.
See also https://wildfiregames.com/forum/index.php?/topic/28525-larger-panel-or-smaller-icons/&tab=comments#comment-401080