Index: binaries/data/mods/public/gui/session/input.js
===================================================================
--- binaries/data/mods/public/gui/session/input.js
+++ binaries/data/mods/public/gui/session/input.js
@@ -1258,9 +1258,27 @@
 
        var selection = g_Selection.toList();
 
+       const orderone = Engine.HotkeyIsPressed("session.orderone");
        var queued = Engine.HotkeyIsPressed("session.queue");
        if (g_UnitActions[action.type] && g_UnitActions[action.type].execute)
+       {
+               // Partly duplicated from doAction()
+               if (orderone)
+               {
+                       // pick the first unit that can do this order.
+                       const unit = selection
+                               .find(entity => ["preSelectedActionCheck", "hotkeyActionCheck", "actionCheck"]
+                                       .some(method => 
+                                               g_UnitActions[action.type][method] &&
+                                               g_UnitActions[action.type][method](action.target || undefined, [entity]))
+                       );
+                       if (unit) {
+                               selection = [unit];
+                               g_Selection.removeList(selection);
+                       }
+               }
                return g_UnitActions[action.type].execute(target, action, selection, queued);
+       }
        error("Invalid action.type " + action.type);
        return false;
 }