diff --git a/docs/user/gui.md b/docs/user/gui.md
index cbc2882..3f71b5e 100644
--- a/docs/user/gui.md
+++ b/docs/user/gui.md
@@ -15,3 +15,9 @@ In `dev`:
 ```
 ./bin/sls_hla_launch_gui.sh qt/A_BD_InjectionGuard.ui dev
 ```
+
+If you need to pass another macro variable in `dev`, you will need to set `AGEBD_ENV_SUFFIX` explicitely:
+
+```
+./bin/sls_hla_launch_gui.sh ./qt/A_BD_Tune.ui dev -macro "AGEBD_ENV_SUFFIX=-DEV, OTHER_ENV_VAR=HEYHEY"
+```