let me make this PAINFULLY CLEAR

core/assets/bundles/bundle.properties

@@ -426,7 +426,8 @@ mode.waves.name=waves
 mode.waves.description=the normal mode. limited resources and automatic incoming waves.
 mode.sandbox.name=sandbox
 mode.sandbox.description=infinite resources and no timer for waves.
-mode.custom.warning=Note that blocks unlocked in custom games are not carried over to sectors.\n\n[LIGHT_GRAY]In sandbox, only blocks unlocked with sector play can be used.
+mode.custom.warning=[scarlet]UNLOCKS IN CUSTOM GAMES OR SERVERS ARE NOT SAVED.[]\n\nPlay in sectors to unlock things.
+mode.custom.warning.read=Just to make sure you've read it:\n[scarlet]UNLOCKS IN CUSTOM GAMES DO NOT CARRY OVER TO SECTORS OR OTHER MODES!\n\n[LIGHT_GRAY](I wish this wasn't necessary, but apparently it is)
 mode.freebuild.name=freebuild
 mode.freebuild.description=limited resources and no timer for waves.
 mode.pvp.name=PvP

core/src/io/anuke/mindustry/core/Control.java

@@ -114,10 +114,13 @@ public class Control extends Module{
 
             state.set(State.playing);
 
-            if(world.getSector() == null && !Settings.getBool("custom-warning", false)){
+            if(world.getSector() == null && !Settings.getBool("custom-warning-for-real-1", false)){
-                threads.runGraphics(() -> ui.showInfo("$mode.custom.warning"));
+                threads.runGraphics(() -> ui.showInfo("$mode.custom.warning", () ->
-                Settings.putBool("custom-warning", true);
+                    ui.showInfo("$mode.custom.warning.read", () -> {
-                Settings.save();
+                        Settings.putBool("custom-warning-for-real-1", true);
+                        Settings.save();
+                    })));
+
             }
         });
 

core/src/io/anuke/mindustry/core/UI.java

@@ -244,6 +244,17 @@ public class UI extends SceneModule{
         }}.show();
     }
 
+    public void showInfo(String info, Runnable clicked){
+        new Dialog("$text.info.title", "dialog"){{
+            getCell(content()).growX();
+            content().margin(15).add(info).width(400f).wrap().get().setAlignment(Align.center, Align.center);
+            buttons().addButton("$text.ok", () -> {
+                clicked.run();
+                hide();
+            }).size(90, 50).pad(4);
+        }}.show();
+    }
+
     public void showError(String text){
         new Dialog("$text.error.title", "dialog"){{
             content().margin(15).add(text).width(400f).wrap().get().setAlignment(Align.center, Align.center);