Explictly return which Qt gui has been enabled.

IPython/terminal/pt_inputhooks/__init__.py

@@ -71,7 +71,7 b' def set_qt_api(gui):'
             print(
                 f"Cannot switch Qt versions for this session; will use {qt_env2gui[loaded]}."
             )
-            return
+            return qt_env2gui[loaded]
 
     if qt_api is not None and gui != "qt":
         if qt_env2gui[qt_api] != gui:
@@ -79,6 +79,7 b' def set_qt_api(gui):'
                 f'Request for "{gui}" will be ignored because `QT_API` '
                 f'environment variable is set to "{qt_api}"'
             )
+            return qt_env2gui[qt_api]
     else:
         if gui == "qt5":
             try:
@@ -110,7 +111,10 b' def set_qt_api(gui):'
                 del os.environ["QT_API"]
         else:
             print(f'Unrecognized Qt version: {gui}. Should be "qt5", "qt6", or "qt".')
-            return
+            return None
+        # Import it now so we can figure out which version it is.
+        from IPython.external.qt_for_kernel import QT_API
+        return qt_env2gui[QT_API]
 
 
 def get_inputhook_name_and_func(gui):
@@ -125,7 +129,7 b' def get_inputhook_name_and_func(gui):'
 
     gui_mod = gui
     if gui.startswith("qt"):
-        set_qt_api(gui)
+        gui = set_qt_api(gui)
         gui_mod = "qt"
 
     mod = importlib.import_module("IPython.terminal.pt_inputhooks." + gui_mod)