// CollapsingHeader returns true when opened but do not indent nor push into the ID stack (because of the ImGuiTreeNodeFlags_NoTreePushOnOpen flag).
// This is basically the same as calling TreeNodeEx(label, ImGuiTreeNodeFlags_CollapsingHeader | ImGuiTreeNodeFlags_NoTreePushOnOpen). You can remove the _NoTreePushOnOpen flag if you want behavior closer to normal TreeNode().
IMGUI_APIvoidTreeAdvanceToLabelPos();// advance cursor x position by GetTreeNodeToLabelSpacing()
IMGUI_APIfloatGetTreeNodeToLabelSpacing();// horizontal distance preceeding label when using TreeNode*() or Bullet() == (g.FontSize + style.FramePadding.x*2) for a regular unframed TreeNode
IMGUI_APIvoidSetNextTreeNodeOpen(boolis_open,ImGuiSetCondcond=0);// set next TreeNode/CollapsingHeader open state.
IMGUI_APIboolCollapsingHeader(constchar*label,ImGuiTreeNodeFlagsflags=0);// if returning 'true' the header is open. user doesn't have to call TreePop().
IMGUI_APIboolCollapsingHeader(constchar*label,ImGuiTreeNodeFlagsflags=0);// if returning 'true' the header is open. doesn't indent nor push on ID stack. user doesn't have to call TreePop().
IMGUI_APIboolCollapsingHeader(constchar*label,bool*p_open,ImGuiTreeNodeFlagsflags=0);// when 'p_open' isn't NULL, display an additional small close button on upper right of the header