VGUI Tooltip

A tooltip is a vgui2 element defined in the vgui_controls library, in the file Tooltip.cpp.

Known Problems with Tooltips

Calling Tooltip::SetText on a tooltip when a tooltip window is visible changes the text for the visible tooltip window. Make sure that you check to make sure no tooltip windows are currently open before calling Tooltip::SetText.

void Tooltip::SetText(const char *text)
{
	_isDirty = true;

	if (!text)
	{
		text = "";
	}

	if (m_Text.Size() > 0)
	{
		m_Text.RemoveAll();
	}

	for (unsigned int i = 0; i < strlen(text); i++)
	{
		m_Text.AddToTail(text[i]);
	}
	m_Text.AddToTail('\0');
	
	if (s_TooltipWindow.Get())
	{
		s_TooltipWindow->SetText(m_Text.Base());
	}
}

The code above was taken from line 89 of tooltip.cpp.

Valve uses a static handler for the current displayed tooltip window (declared on line 28 of tooltip.cpp), static vgui::DHANDLE< TextEntry > s_TooltipWindow;.

I'm not sure why, but as you can see in the code above, towards the end of the function Tooltip::SetText, it changes the text of the active tooltip window. Valve needs to remove this from their code to fix this bug.