diff --git a/dlls/mshtml/mshtml_private.h b/dlls/mshtml/mshtml_private.h
index 59d652a828b..9a606c4e501 100644
--- a/dlls/mshtml/mshtml_private.h
+++ b/dlls/mshtml/mshtml_private.h
@@ -337,14 +337,31 @@ typedef struct dispex_dynamic_data_t dispex_dynamic_data_t;
 
 typedef struct DispatchEx DispatchEx;
 
+/*
+   dispex is our base IDispatchEx implementation for all mshtml objects, and the vtbl allows
+   customizing the behavior depending on the object. Objects have basically 3 types of props:
+
+   - builtin props: These props are implicitly generated from the TypeInfo (disp_tid and iface_tids in dispex_static_data_t).
+   - custom props:  These props are specific to an object, they are created using vtbl below (e.g. indexed props in HTMLRectCollection).
+   - dynamic props: These props are generally allocated by external code (e.g. 'document.wine = 42' creates 'wine' dynamic prop on document)
+*/
 typedef struct {
+    /* Called when the object wants to handle DISPID_VALUE invocations */
     HRESULT (*value)(DispatchEx*,LCID,WORD,DISPPARAMS*,VARIANT*,EXCEPINFO*,IServiceProvider*);
+
+    /* Used when the object has custom props, and this returns DISPIDs for them */
     HRESULT (*get_dispid)(DispatchEx*,BSTR,DWORD,DISPID*);
+
+    /* These are called when the object implements GetMemberName, InvokeEx, DeleteMemberByDispID and GetNextDispID for custom props */
     HRESULT (*get_name)(DispatchEx*,DISPID,BSTR*);
     HRESULT (*invoke)(DispatchEx*,DISPID,LCID,WORD,DISPPARAMS*,VARIANT*,EXCEPINFO*,IServiceProvider*);
     HRESULT (*delete)(DispatchEx*,DISPID);
     HRESULT (*next_dispid)(DispatchEx*,DISPID,DISPID*);
+
+    /* Used by objects that want to delay their compat mode initialization until actually needed */
     compat_mode_t (*get_compat_mode)(DispatchEx*);
+
+    /* Used by objects that want to populate some dynamic props on initialization */
     HRESULT (*populate_props)(DispatchEx*);
 } dispex_static_data_vtbl_t;