From f2699de24241bedad05b18dfe5beba623ba77dcf Mon Sep 17 00:00:00 2001
From: ocornut <omarcornut@gmail.com>
Date: Sun, 25 Sep 2016 14:18:10 +0200
Subject: [PATCH] Fix using IsItemActive() after EndGroup() or any widget using
 groups (#840, #479)

---
 imgui.cpp        | 19 ++++++++++++-------
 imgui_internal.h |  1 +
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/imgui.cpp b/imgui.cpp
index 71cc3a42b..afd587246 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -7609,11 +7609,13 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
     const ImGuiIO& io = g.IO;
     const ImGuiStyle& style = g.Style;
 
-    const ImGuiID id = window->GetID(label);
     const bool is_multiline = (flags & ImGuiInputTextFlags_Multiline) != 0;
     const bool is_editable = (flags & ImGuiInputTextFlags_ReadOnly) == 0;
     const bool is_password = (flags & ImGuiInputTextFlags_Password) != 0;
 
+    if (is_multiline) // Open group before calling GetID() because groups tracks id created during their spawn
+        BeginGroup();
+    const ImGuiID id = window->GetID(label);
     const ImVec2 label_size = CalcTextSize(label, NULL, true);
     ImVec2 size = CalcItemSize(size_arg, CalcItemWidth(), (is_multiline ? GetTextLineHeight() * 8.0f : label_size.y) + style.FramePadding.y*2.0f); // Arbitrary default of 8 lines high for multi-line
     const ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + size);
@@ -7622,7 +7624,6 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
     ImGuiWindow* draw_window = window;
     if (is_multiline)
     {
-        BeginGroup();
         if (!BeginChildFrame(id, frame_bb.GetSize()))
         {
             EndChildFrame();
@@ -8149,8 +8150,6 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
         Dummy(text_size + ImVec2(0.0f, g.FontSize)); // Always add room to scroll an extra line
         EndChildFrame();
         EndGroup();
-        if (g.ActiveId == id || is_currently_scrolling) // Set LastItemId which was lost by EndChild/EndGroup, so user can use IsItemActive()
-            window->DC.LastItemId = g.ActiveId;
     }
 
     if (is_password)
@@ -8204,7 +8203,7 @@ bool ImGui::InputScalarEx(const char* label, ImGuiDataType data_type, void* data
     if (!(extra_flags & ImGuiInputTextFlags_CharsHexadecimal))
         extra_flags |= ImGuiInputTextFlags_CharsDecimal;
     extra_flags |= ImGuiInputTextFlags_AutoSelectAll;
-    if (InputText("", buf, IM_ARRAYSIZE(buf), extra_flags))
+    if (InputText("", buf, IM_ARRAYSIZE(buf), extra_flags)) // PushId(label) + "" gives us the expected ID from outside point of view
         value_changed = DataTypeApplyOpFromText(buf, GImGui->InputTextState.InitialText.begin(), data_type, data_ptr, scalar_format);
 
     // Step buttons
@@ -9155,6 +9154,7 @@ void ImGui::BeginGroup()
     group_data.BackupCurrentLineHeight = window->DC.CurrentLineHeight;
     group_data.BackupCurrentLineTextBaseOffset = window->DC.CurrentLineTextBaseOffset;
     group_data.BackupLogLinePosY = window->DC.LogLinePosY;
+    group_data.BackupActiveIdIsAlive = GImGui->ActiveIdIsAlive;
     group_data.AdvanceCursor = true;
 
     window->DC.GroupOffsetX = window->DC.CursorPos.x - window->Pos.x - window->DC.ColumnsOffsetX;
@@ -9166,15 +9166,15 @@ void ImGui::BeginGroup()
 
 void ImGui::EndGroup()
 {
+    ImGuiContext& g = *GImGui;
     ImGuiWindow* window = GetCurrentWindow();
-    ImGuiStyle& style = GetStyle();
 
     IM_ASSERT(!window->DC.GroupStack.empty());	// Mismatched BeginGroup()/EndGroup() calls
 
     ImGuiGroupData& group_data = window->DC.GroupStack.back();
 
     ImRect group_bb(group_data.BackupCursorPos, window->DC.CursorMaxPos);
-    group_bb.Max.y -= style.ItemSpacing.y;      // Cancel out last vertical spacing because we are adding one ourselves.
+    group_bb.Max.y -= g.Style.ItemSpacing.y;      // Cancel out last vertical spacing because we are adding one ourselves.
     group_bb.Max = ImMax(group_bb.Min, group_bb.Max);
 
     window->DC.CursorPos = group_data.BackupCursorPos;
@@ -9192,6 +9192,11 @@ void ImGui::EndGroup()
         ItemAdd(group_bb, NULL);
     }
 
+    // If the current ActiveId was declared within the boundary of our group, we copy it to LastItemId so IsItemActive() will function on the entire group.
+    // It would be be neater if we replaced window.DC.LastItemId by e.g. 'bool LastItemIsActive', but if you search for LastItemId you'll notice it is only used in that context.
+    if (!group_data.BackupActiveIdIsAlive && g.ActiveIdIsAlive && g.ActiveId && g.ActiveIdWindow->RootWindow == window->RootWindow)
+        window->DC.LastItemId = g.ActiveId;
+
     window->DC.GroupStack.pop_back();
 
     //window->DrawList->AddRect(group_bb.Min, group_bb.Max, 0xFFFF00FF);   // Debug
diff --git a/imgui_internal.h b/imgui_internal.h
index f4a0d6889..4bfec9dcd 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -266,6 +266,7 @@ struct ImGuiGroupData
     float       BackupCurrentLineHeight;
     float       BackupCurrentLineTextBaseOffset;
     float       BackupLogLinePosY;
+    bool        BackupActiveIdIsAlive;
     bool        AdvanceCursor;
 };