ImVector: Added find_index() helper.

docs/CHANGELOG.txt

@@ -60,6 +60,7 @@ Other changes:
   register contents size in a way that would affect the scrolling layer.
   Was most often noticable when using an horizontal scrollbar. (#6789)
 - ImDrawList: Added AddEllipse(), AddEllipseFilled(), PathEllipticalArcTo(). (#2743) [@Doohl]
+- ImVector: Added find_index() helper.
 - Backends: GLFW: Clear emscripten's MouseWheel callback before shutdown. (#6790, #6096, #4019) [@halx99]
 - Backends: Win32: Added support for keyboard codepage conversion for when application
   is compiled in MBCS mode and using a non-Unicode window. (#6785, #6782, #5725, #5961) [@sneakyevil]

imgui.cpp

@@ -2698,8 +2698,6 @@ void ImGuiTextIndex::append(const char* base, int old_size, int new_size)
 
 //-----------------------------------------------------------------------------
 // [SECTION] ImGuiListClipper
-// This is currently not as flexible/powerful as it should be and really confusing/spaghetti, mostly because we changed
-// the API mid-way through development and support two ways to using the clipper, needs some rework (see TODO)
 //-----------------------------------------------------------------------------
 
 // FIXME-TABLE: This prevents us from using ImGuiListClipper _inside_ a table cell.

imgui.h

@@ -1868,6 +1868,7 @@ struct ImVector
     inline bool         contains(const T& v) const          { const T* data = Data;  const T* data_end = Data + Size; while (data < data_end) if (*data++ == v) return true; return false; }
     inline T*           find(const T& v)                    { T* data = Data;  const T* data_end = Data + Size; while (data < data_end) if (*data == v) break; else ++data; return data; }
     inline const T*     find(const T& v) const              { const T* data = Data;  const T* data_end = Data + Size; while (data < data_end) if (*data == v) break; else ++data; return data; }
+    inline int          find_index(const T& v) const        { const T* data_end = Data + Size; const T* it = find(v); if (it == data_end) return -1; const ptrdiff_t off = it - Data; return (int)off; }
     inline bool         find_erase(const T& v)              { const T* it = find(v); if (it < Data + Size) { erase(it); return true; } return false; }
     inline bool         find_erase_unsorted(const T& v)     { const T* it = find(v); if (it < Data + Size) { erase_unsorted(it); return true; } return false; }
     inline int          index_from_ptr(const T* it) const   { IM_ASSERT(it >= Data && it < Data + Size); const ptrdiff_t off = it - Data; return (int)off; }