Added extra comments and assertions to avoid user combining ImGuiCond flags. (#1694)

CHANGELOG.txt

@@ -206,7 +206,8 @@ Breaking Changes:
 - Renamed `ImGuiTextBuffer::append()` helper to `appendf()`, and `appendv()` to `appendfv()` for consistency. If you copied the 'Log' demo in your code, it uses appendv() so that needs to be renamed.
 - ImDrawList: Removed 'bool anti_aliased = true' final parameter of `ImDrawList::AddPolyline()` and `ImDrawList::AddConvexPolyFilled()`. Prefer manipulating ImDrawList::Flags if you need to toggle them during the frame.
 - Style, ImDrawList: Renamed `style.AntiAliasedShapes` to `style.AntiAliasedFill` for consistency and as a way to explicitly break code that manipulate those flag at runtime. You can now manipulate ImDrawList::Flags.
-- Style, Begin: Removed `ImGuiWindowFlags_ShowBorders` window flag. Borders are now fully set up in the ImGuiStyle structure (see e.g. `style.FrameBorderSize`, `style.WindowBorderSize`). Use `ImGui::ShowStyleEditor()` to look them up.
+- Style, Begin: Removed `ImGuiWindowFlags_ShowBorders` window flag. Borders are now fully set up in the ImGuiStyle structure (see e.g. `style.FrameBorderSize`, `style.WindowBorderSize`, `style.PopupBorderSize`). 
+  Use `ImGui::ShowStyleEditor()` to look them up.
   Please note that the style system will keep evolving (hopefully stabilizing in Q1 2018), and so custom styles will probably subtly break over time. 
   It is recommended that you use the `StyleColorsClassic()`, `StyleColorsDark()`, `StyleColorsLight()` functions. Also see `ShowStyleSelector()`.
 - Style: Removed `ImGuiCol_ComboBg` in favor of combo boxes using `ImGuiCol_PopupBg` for consistency. Combo are normal popups.
@@ -231,7 +232,8 @@ Other Changes:
 - Style: Added StyleColorsDark() style. (#707) [@dougbinks]
 - Style: Added StyleColorsLight() style. Best used with frame borders + thicker font than the default font. (#707)
 - Style: Added style.PopupRounding setting. (#1112) 
-- Style: Added style.FrameBorderSize, style.WindowBorderSize. Removed ImGuiWindowFlags_ShowBorders window flag! Borders are now fully set up in the ImGuiStyle structure. Use ImGui::ShowStyleEditor() to look them up. (#707, fix #819, #1031)
+- Style: Added style.FrameBorderSize, style.WindowBorderSize, style.PopupBorderSize. Removed ImGuiWindowFlags_ShowBorders window flag! 
+  Borders are now fully set up in the ImGuiStyle structure. Use ImGui::ShowStyleEditor() to look them up. (#707, fix #819, #1031)
 - Style: Various small changes to the classic style (most noticeably, buttons are now using blue shades). (#707)
 - Style: Renamed ImGuiCol_ChildWindowBg to ImGuiCol_ChildBg. 
 - Style: Renamed style.ChildWindowRounding to style.ChildRounding, ImGuiStyleVar_ChildWindowRounding to ImGuiStyleVar_ChildRounding.
@@ -261,6 +263,7 @@ Other Changes:
 - Window: Using the ImGuiWindowFlags_NoScrollWithMouse flag on a child window forwards the mouse wheel event to the parent window, unless either ImGuiWindowFlags_NoInputs or ImGuiWindowFlags_NoScrollbar are also set. (#1380, #1502)
 - Window: Active Modal window always set the WantCaptureKeyboard flag. (#744) 
 - Window: Moving window doesn't use accumulating MouseDelta so straying out of imgui boundaries keeps moved imgui window at the same cursor-relative position.
+- Window: BeginChild() which an explicit name doesn't include the hash within the internal window name. (#1698) 
 - IsWindowFocused(): Added ImGuiFocusedFlags_ChildWindows flag to include child windows in the focused test. (#1382).
 - IsWindowFocused(): Added ImGuiFocusedFlags_RootWindow flag to start focused test from the root (top-most) window. Obsolete IsRootWindowFocused(). (#1382)
 - IsWindowHovered(): Added ImGuiHoveredFlags_ChildWindows flag to include child windows in the hovered test. (#1382).

imgui.cpp

@@ -6846,6 +6846,8 @@ static void SetWindowPos(ImGuiWindow* window, const ImVec2& pos, ImGuiCond cond)
     // Test condition (NB: bit 0 is always true) and clear flags for next time
     if (cond && (window->SetWindowPosAllowFlags & cond) == 0)
         return;
+
+    IM_ASSERT(cond == 0 || ImIsPowerOfTwo(cond)); // Make sure the user doesn't attempt to combine multiple condition flags.
     window->SetWindowPosAllowFlags &= ~(ImGuiCond_Once | ImGuiCond_FirstUseEver | ImGuiCond_Appearing);
     window->SetWindowPosVal = ImVec2(FLT_MAX, FLT_MAX);
 
@@ -6880,6 +6882,8 @@ static void SetWindowSize(ImGuiWindow* window, const ImVec2& size, ImGuiCond con
     // Test condition (NB: bit 0 is always true) and clear flags for next time
     if (cond && (window->SetWindowSizeAllowFlags & cond) == 0)
         return;
+
+    IM_ASSERT(cond == 0 || ImIsPowerOfTwo(cond)); // Make sure the user doesn't attempt to combine multiple condition flags.
     window->SetWindowSizeAllowFlags &= ~(ImGuiCond_Once | ImGuiCond_FirstUseEver | ImGuiCond_Appearing);
 
     // Set
@@ -6971,6 +6975,7 @@ void ImGui::SetWindowFocus(const char* name)
 void ImGui::SetNextWindowPos(const ImVec2& pos, ImGuiCond cond, const ImVec2& pivot)
 {
     ImGuiContext& g = *GImGui;
+    IM_ASSERT(cond == 0 || ImIsPowerOfTwo(cond)); // Make sure the user doesn't attempt to combine multiple condition flags.
     g.NextWindowData.PosVal = pos;
     g.NextWindowData.PosPivotVal = pivot;
     g.NextWindowData.PosCond = cond ? cond : ImGuiCond_Always;
@@ -6979,6 +6984,7 @@ void ImGui::SetNextWindowPos(const ImVec2& pos, ImGuiCond cond, const ImVec2& pi
 void ImGui::SetNextWindowSize(const ImVec2& size, ImGuiCond cond)
 {
     ImGuiContext& g = *GImGui;
+    IM_ASSERT(cond == 0 || ImIsPowerOfTwo(cond)); // Make sure the user doesn't attempt to combine multiple condition flags.
     g.NextWindowData.SizeVal = size;
     g.NextWindowData.SizeCond = cond ? cond : ImGuiCond_Always;
 }
@@ -7002,6 +7008,7 @@ void ImGui::SetNextWindowContentSize(const ImVec2& size)
 void ImGui::SetNextWindowCollapsed(bool collapsed, ImGuiCond cond)
 {
     ImGuiContext& g = *GImGui;
+    IM_ASSERT(cond == 0 || ImIsPowerOfTwo(cond)); // Make sure the user doesn't attempt to combine multiple condition flags.
     g.NextWindowData.CollapsedVal = collapsed;
     g.NextWindowData.CollapsedCond = cond ? cond : ImGuiCond_Always;
 }

imgui.h

@@ -937,7 +937,7 @@ enum ImGuiMouseCursor_
 };
 
 // Condition for ImGui::SetWindow***(), SetNextWindow***(), SetNextTreeNode***() functions
-// All those functions treat 0 as a shortcut to ImGuiCond_Always. From the point of view of the user use this as an enum (don't combine multiple values into flags).
+// Important: Treat as a regular enum! Do NOT combine multiple values using binary operators! All the functions above treat 0 as a shortcut to ImGuiCond_Always. 
 enum ImGuiCond_
 {
     ImGuiCond_Always        = 1 << 0,   // Set the variable