Misc tweaks/fixes (see details).

Combo: ultra minor fix for popup positioning policy mismatch depending on ImGuiComboFlags_PopupAlignLeft flag.
Made ImHashXXX functions return ImGuiID.
IsWindowNavFocusable use !WasActive.. it worked because it was only called in NewFrame()->NavUpdate() before the transition loop + EndFrame() only.
Fix unused variable warning.

imgui.cpp

@@ -1433,7 +1433,7 @@ static const ImU32 GCrc32LookupTable[256] =
 // Known size hash
 // It is ok to call ImHashData on a string with known length but the ### operator won't be supported.
 // FIXME-OPT: Replace with e.g. FNV1a hash? CRC32 pretty much randomly access 1KB. Need to do proper measurements.
-ImU32 ImHashData(const void* data_p, size_t data_size, ImU32 seed)
+ImGuiID ImHashData(const void* data_p, size_t data_size, ImU32 seed)
 {
     ImU32 crc = ~seed;
     const unsigned char* data = (const unsigned char*)data_p;
@@ -1449,7 +1449,7 @@ ImU32 ImHashData(const void* data_p, size_t data_size, ImU32 seed)
 // - If we reach ### in the string we discard the hash so far and reset to the seed.
 // - We don't do 'current += 2; continue;' after handling ### to keep the code smaller/faster (measured ~10% diff in Debug build)
 // FIXME-OPT: Replace with e.g. FNV1a hash? CRC32 pretty much randomly access 1KB. Need to do proper measurements.
-ImU32 ImHashStr(const char* data_p, size_t data_size, ImU32 seed)
+ImGuiID ImHashStr(const char* data_p, size_t data_size, ImU32 seed)
 {
     seed = ~seed;
     ImU32 crc = seed;
@@ -6405,7 +6405,7 @@ bool ImGui::IsWindowFocused(ImGuiFocusedFlags flags)
 // If you want a window to never be focused, you may use the e.g. NoInputs flag.
 bool ImGui::IsWindowNavFocusable(ImGuiWindow* window)
 {
-    return window->Active && window == window->RootWindow && !(window->Flags & ImGuiWindowFlags_NoNavFocus);
+    return window->WasActive && window == window->RootWindow && !(window->Flags & ImGuiWindowFlags_NoNavFocus);
 }
 
 float ImGui::GetWindowWidth()
@@ -7002,6 +7002,7 @@ void ImGuiStackSizes::CompareWithCurrentState()
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
+    IM_UNUSED(window);
 
     // Window stacks
     // NOT checking: DC.ItemWidth, DC.TextWrapPos (per window) to allow user to conveniently push once and not pop (they are cleared on Begin)

imgui.h

@@ -371,9 +371,9 @@ namespace ImGui
     IMGUI_API ImU32         GetColorU32(ImU32 col);                                         // retrieve given color with style alpha applied
 
     // Parameters stacks (current window)
-    IMGUI_API void          PushItemWidth(float item_width);                                // push width of items for common large "item+label" widgets. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -1.0f always align width to the right side). 0.0f = default to ~2/3 of windows width,
+    IMGUI_API void          PushItemWidth(float item_width);                                // push width of items for common large "item+label" widgets. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -FLT_MIN always align width to the right side). 0.0f = default to ~2/3 of windows width,
     IMGUI_API void          PopItemWidth();
-    IMGUI_API void          SetNextItemWidth(float item_width);                             // set width of the _next_ common large "item+label" widget. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -1.0f always align width to the right side)
+    IMGUI_API void          SetNextItemWidth(float item_width);                             // set width of the _next_ common large "item+label" widget. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -FLT_MIN always align width to the right side)
     IMGUI_API float         CalcItemWidth();                                                // width of item given pushed settings and current cursor position. NOT necessarily the width of last item unlike most 'Item' functions.
     IMGUI_API void          PushTextWrapPos(float wrap_local_pos_x = 0.0f);                 // push word-wrapping position for Text*() commands. < 0.0f: no wrapping; 0.0f: wrap to end of window (or column); > 0.0f: wrap at 'wrap_pos_x' position in window local space
     IMGUI_API void          PopTextWrapPos();

imgui_internal.h

@@ -250,10 +250,10 @@ namespace ImStb
 //-----------------------------------------------------------------------------
 
 // Helpers: Hashing
-IMGUI_API ImU32         ImHashData(const void* data, size_t data_size, ImU32 seed = 0);
-IMGUI_API ImU32         ImHashStr(const char* data, size_t data_size = 0, ImU32 seed = 0);
+IMGUI_API ImGuiID       ImHashData(const void* data, size_t data_size, ImU32 seed = 0);
+IMGUI_API ImGuiID       ImHashStr(const char* data, size_t data_size = 0, ImU32 seed = 0);
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
-static inline ImU32     ImHash(const void* data, int size, ImU32 seed = 0) { return size ? ImHashData(data, (size_t)size, seed) : ImHashStr((const char*)data, 0, seed); } // [moved to ImHashStr/ImHashData in 1.68]
+static inline ImGuiID   ImHash(const void* data, int size, ImU32 seed = 0) { return size ? ImHashData(data, (size_t)size, seed) : ImHashStr((const char*)data, 0, seed); } // [moved to ImHashStr/ImHashData in 1.68]
 #endif
 
 // Helpers: Sorting

imgui_widgets.cpp

@@ -1590,13 +1590,17 @@ bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboF
     char name[16];
     ImFormatString(name, IM_ARRAYSIZE(name), "##Combo_%02d", g.BeginPopupStack.Size); // Recycle windows based on depth
 
-    // Peak into expected window size so we can position it
+    // Position the window given a custom constraint (peak into expected window size so we can position it)
+    // This might be easier to express with an hypothetical SetNextWindowPosConstraints() function.
     if (ImGuiWindow* popup_window = FindWindowByName(name))
         if (popup_window->WasActive)
         {
+            // Always override 'AutoPosLastDirection' to not leave a chance for a past value to affect us.
             ImVec2 size_expected = CalcWindowExpectedSize(popup_window);
             if (flags & ImGuiComboFlags_PopupAlignLeft)
-                popup_window->AutoPosLastDirection = ImGuiDir_Left;
+                popup_window->AutoPosLastDirection = ImGuiDir_Left; // "Below, Toward Left"
+            else
+                popup_window->AutoPosLastDirection = ImGuiDir_Down; // "Below, Toward Right (default)"
             ImRect r_outer = GetWindowAllowedExtentRect(popup_window);
             ImVec2 pos = FindBestWindowPosForPopupEx(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
             SetNextWindowPos(pos);