On-demand loading of tooltip (XHTML) text
Change the signature of the virtual WWidget::toolTip() function:
virtual WString toolTip() const
The base implementation is as currently (i.e. returns text set by setToolTip()) but user can reimplement it to have on-demand loading of the tooltip text.
ToolTip.js should be modified to fetch the tool tip text using a JSignal.
In WItemDelegate modify so that the WText::setToolTip() does not actually fetch the tooltip; probably it needs a new flag to indicate the availability of tooltip data. If the flag is not present we keep the current behavior; otherwise we get the new behavior with a specialized WText::toolTip().