InputTextMultiline(): partial fix for when input and internal buffers differs in a way where scrollbar existence differs. (#725)

Partial fix, won't stop ids from functioning because of a zombie id.

imgui.cpp

@@ -1776,6 +1776,12 @@ ImGuiID ImGuiWindow::GetID(const void* ptr)
     return id;
 }
 
+ImGuiID ImGuiWindow::GetIDNoKeepAlive(const char* str, const char* str_end)
+{
+    ImGuiID seed = IDStack.back();
+    return ImHash(str, str_end ? (int)(str_end - str) : 0, seed);
+}
+
 //-----------------------------------------------------------------------------
 // Internal API exposed in imgui_internal.h
 //-----------------------------------------------------------------------------
@@ -7633,7 +7639,7 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
         g.MouseCursor = ImGuiMouseCursor_TextInput;
     }
     const bool user_clicked = hovered && io.MouseClicked[0];
-    const bool user_scrolled = is_multiline && g.ActiveId == 0 && edit_state.Id == id && g.ActiveIdPreviousFrame == draw_window->GetID("#SCROLLY");
+    const bool user_scrolled = is_multiline && g.ActiveId == 0 && edit_state.Id == id && g.ActiveIdPreviousFrame == draw_window->GetIDNoKeepAlive("#SCROLLY");
 
     bool select_all = (g.ActiveId != id) && (flags & ImGuiInputTextFlags_AutoSelectAll) != 0;
     if (focus_requested || user_clicked || user_scrolled)
@@ -7954,7 +7960,7 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
     const ImVec4 clip_rect(frame_bb.Min.x, frame_bb.Min.y, frame_bb.Min.x + size.x, frame_bb.Min.y + size.y); // Not using frame_bb.Max because we have adjusted size
     ImVec2 render_pos = is_multiline ? draw_window->DC.CursorPos : frame_bb.Min + style.FramePadding;
     ImVec2 text_size(0.f, 0.f);
-    if (g.ActiveId == id || (edit_state.Id == id && is_multiline && g.ActiveId == draw_window->GetID("#SCROLLY")))
+    if (g.ActiveId == id || (edit_state.Id == id && is_multiline && g.ActiveId == draw_window->GetIDNoKeepAlive("#SCROLLY")))
     {
         edit_state.CursorAnim += g.IO.DeltaTime;
 

imgui_internal.h

@@ -657,6 +657,7 @@ public:
 
     ImGuiID     GetID(const char* str, const char* str_end = NULL);
     ImGuiID     GetID(const void* ptr);
+    ImGuiID     GetIDNoKeepAlive(const char* str, const char* str_end = NULL);
 
     ImRect      Rect() const                            { return ImRect(Pos.x, Pos.y, Pos.x+Size.x, Pos.y+Size.y); }
     float       CalcFontSize() const                    { return GImGui->FontBaseSize * FontWindowScale; }