diff --git a/tasks/horizon_install_source.yml b/tasks/horizon_install_source.yml
index 76998a79..c7662590 100644
--- a/tasks/horizon_install_source.yml
+++ b/tasks/horizon_install_source.yml
@@ -51,7 +51,7 @@
     name: "python_venv_build"
   vars:
     venv_python_executable: "{{ horizon_venv_python_executable }}"
-    venv_build_constraints: "{{ _u_c_contents.content.split('\n') | reject('match', '[horizon=*]') | list }}"
+    venv_build_constraints: "{{ _u_c_contents.content.split('\n') | reject('match', '^horizon=') | list }}"
     venv_build_distro_package_list: "{{ horizon_devel_distro_packages }}"
     venv_install_destination_path: "{{ horizon_bin | dirname }}"
     venv_pip_install_args: "{{ horizon_pip_install_args }}"
@@ -175,4 +175,4 @@
   with_items: "{{ found_panels.files }}"
   notify:
     - Compile messages
-    - Restart apache2
\ No newline at end of file
+    - Restart apache2