Bill of materials to be done before starting this ticket:

• Add unsynced wupget:ActiveCommandSet(cmdID) #1091

This is a map-side setting which cannot be controlled by a game, and which makes it so that the metal view is force-enabled when "build mex" becomes the active command.

Gameside control can already be achieved via Lua. Right now it has to be polling, but with #1091 a replacement should become as simple as:

function widget:ActiveCommandSet(cmdID)
  local isMex = cmdID < 0 and UnitDefs[-cmdID].extractsMetal > 0
  local isMetalViewOn = (Spring.GetMapDrawMode() == 'metal')
  if isMex ~= isMetalViewOn then
    Spring.SendCommands("showmetalmap")
  end
end

Therefore the proposal is to remove the mapside tag.