Begin: FIx previous commit - no need to call on collapsed window. Handle manual resize (grip, border, gamepad) before setting up window DrawList main clipping rectangle. Sane (and required for viewport code). (#822, #1542)

imgui.cpp

@@ -4750,7 +4750,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         ImU32 resize_grip_col[4] = { 0 };
         const int resize_grip_count = (flags & ImGuiWindowFlags_ResizeFromAnySide) ? 2 : 1; // 4
         const float grip_draw_size = (float)(int)ImMax(g.FontSize * 1.35f, window->WindowRounding + 1.0f + g.FontSize * 0.2f);
-        UpdateManualResize(window, size_auto_fit, &border_held, resize_grip_count, &resize_grip_col[0]);
+        if (!window->Collapsed)
+            UpdateManualResize(window, size_auto_fit, &border_held, resize_grip_count, &resize_grip_col[0]);
 
         // DRAWING