Removed DisplayVisibleMin/DisplayVisibleMax facility (as part of # 1542). Misc comments.

imgui.cpp

@@ -250,6 +250,7 @@
  Here is a change-log of API breaking changes, if you are using one of the functions listed, expect to have to fix some code.
  Also read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2018/02/27 (1.XX) - removed io.DisplayVisibleMin, io.DisplayVisibleMax settings (it was used to clip within the DisplayPos..DisplayPos+Size range, I don't know of anyone using it)
  - 2018/02/18 (1.60) - BeginDragDropSource(): temporarily removed the optional mouse_button=0 parameter because it is not really usable in many situations at the moment. 
  - 2018/02/16 (1.60) - obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render(). Use ImGui::GetDrawData() to retrieve the ImDrawData* to display.
  - 2018/02/07 (1.60) - reorganized context handling to be more explicit,
@@ -864,7 +865,6 @@ ImGuiIO::ImGuiIO()
     FontDefault = NULL;
     FontAllowUserScaling = false;
     DisplayFramebufferScale = ImVec2(1.0f, 1.0f);
-    DisplayVisibleMin = DisplayVisibleMax = ImVec2(0.0f, 0.0f);
 
     // Advanced/subtle behaviors
 #ifdef __APPLE__
@@ -4747,8 +4747,6 @@ ImVec2 ImGui::GetItemRectSize()
 static ImRect GetViewportRect()
 {
     ImGuiContext& g = *GImGui;
-    if (g.IO.DisplayVisibleMin.x != g.IO.DisplayVisibleMax.x && g.IO.DisplayVisibleMin.y != g.IO.DisplayVisibleMax.y)
-        return ImRect(g.IO.DisplayVisibleMin, g.IO.DisplayVisibleMax);
     return ImRect(0.0f, 0.0f, g.IO.DisplaySize.x, g.IO.DisplaySize.y);
 }