Layout: Fixed mixing up SameLine() and SetCursorPos() together. SameLine() is a stateful.

+ minor unrelatedcomments.

imgui_internal.h

@@ -1979,6 +1979,7 @@ struct IMGUI_API ImGuiWindowTempData
     ImVec2                  PrevLineSize;
     float                   CurrLineTextBaseOffset; // Baseline offset (0.0f by default on a new line, generally == style.FramePadding.y when a framed item has been added).
     float                   PrevLineTextBaseOffset;
+    bool                    IsSameLine;
     ImVec1                  Indent;                 // Indentation / start position from left of window (increased by TreePush/TreePop, etc.)
     ImVec1                  ColumnsOffset;          // Offset to the current column (if ColumnsCurrent > 0). FIXME: This and the above should be a stack to allow use cases like Tree->Column->Tree. Need revamp columns API.
     ImVec1                  GroupOffset;