diff --git a/Source/exehead/Ui.c b/Source/exehead/Ui.c
index 9035db8b..58dd7c8a 100644
--- a/Source/exehead/Ui.c
+++ b/Source/exehead/Ui.c
@@ -1244,7 +1244,7 @@ static BOOL CALLBACK SelProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lPar
               SectionFlagsChanged(tvItem.lParam);
 
               wParam = 1;
-              lParam = 1;
+              lParam = !(g_flags & CH_FLAGS_COMP_ONLY_ON_CUSTOM);
               uMsg = WM_IN_UPDATEMSG;
             }
           }
@@ -1282,6 +1282,8 @@ static BOOL CALLBACK SelProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lPar
 
       SetInstType(whichcfg);
 
+      SendMessage(hwndDlg, WM_NOTIFY_INSTTYPE_CHANGED, 0, whichcfg);
+
       wParam = 1;
       lParam = 0;
       uMsg = WM_IN_UPDATEMSG;
@@ -1315,38 +1317,22 @@ static BOOL CALLBACK SelProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lPar
 
     if (lParam)
     {
-      if (g_flags & CH_FLAGS_COMP_ONLY_ON_CUSTOM)
+      int i, cbi;
+      int inst_type = GetInstType(hTreeItems);
+      SetInstType(inst_type);
+
+      for (i = 0, cbi = 0; i < inst_type; i++)
       {
-        int c = SW_SHOWNA;
-
-        int t = SendMessage(hwndCombo1,CB_GETCURSEL,0,0);
-        if (t != CB_ERR)
+        if (install_types[i])
         {
-          int whichcfg = SendMessage(hwndCombo1, CB_GETITEMDATA, t, 0);
-
-          if (whichcfg != CB_ERR && install_types[whichcfg] && whichcfg != NSIS_MAX_INST_TYPES)
-            c = SW_HIDE;
+          cbi++;
         }
-
-        ShowWindow(hwndTree1, c);
-        ShowWindow(GetUIItem(IDC_TEXT2), c);
       }
-      else
-      {
-        int i, cbi;
-        int inst_type = GetInstType(hTreeItems);
-        SetInstType(inst_type);
 
-        for (i = 0, cbi = 0; i < inst_type; i++)
-        {
-          if (install_types[i])
-          {
-            cbi++;
-          }
-        }
+      SendMessage(hwndCombo1, CB_SETCURSEL, cbi, 0);
 
-        SendMessage(hwndCombo1, CB_SETCURSEL, cbi, 0);
-      } // end of typecheckshit
+      lParam = inst_type;
+      uMsg = WM_NOTIFY_INSTTYPE_CHANGED;
     }
 
     RefreshSectionGroups();
@@ -1357,6 +1343,16 @@ static BOOL CALLBACK SelProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lPar
     }
   }
 
+  if (uMsg == WM_NOTIFY_INSTTYPE_CHANGED)
+  {
+    if (g_flags & CH_FLAGS_COMP_ONLY_ON_CUSTOM)
+    {
+      int c = (lParam == NSIS_MAX_INST_TYPES ? 1 : 0) << 3;// SW_SHOWNA=8, SW_HIDE=0
+      ShowWindow(hwndTree1, c);
+      ShowWindow(GetUIItem(IDC_TEXT2), c);
+    }
+  }
+
   return HandleStaticBkColor();
 }
 #endif//NSIS_CONFIG_COMPONENTPAGE
diff --git a/Source/exehead/ui.h b/Source/exehead/ui.h
index 28368f37..fd8545f5 100644
--- a/Source/exehead/ui.h
+++ b/Source/exehead/ui.h
@@ -29,22 +29,16 @@ void NSISCALL build_g_logfile(void);
 // update message used by DirProc and SelProc for space display
 #define WM_IN_UPDATEMSG (WM_USER+0xf)
 
-// the selected insttype has changed
-#define WM_NOTIFY_INSTTYPE_CHANGE (WM_USER+0x32)
-
 // custom pages should send this message to let NSIS know they're ready
 #define WM_NOTIFY_CUSTOM_READY (WM_USER+0xd)
 
 // simulates clicking on the tree
 #define WM_TREEVIEW_KEYHACK (WM_USER+0x13)
 
-// section text changed
-#define WM_NOTIFY_SECTEXT (WM_USER+0x17)
-
-// section flags changed
-#define WM_NOTIFY_SECFLAGS (WM_USER+0x18)
-
 // notifies a component selection change (.onMouseOverSection)
 #define WM_NOTIFY_SELCHANGE (WM_USER+0x19)
 
+// Notifies the installation type has changed by the user
+#define WM_NOTIFY_INSTTYPE_CHANGED (WM_USER+0x20)
+
 #endif//_UI_H_