Re-wrote nsComboboxFrame.
removed the obsolete nsHTMLAtoms: comboText,comoTextSelected,comTextSelectedFocus,dropDownVisible,
dropdownHidden, dropDownBtnOut, dropDownBtnPressed,
Added nsHTMLAtoms::combobox, nsLayoutAtoms::popupList
Renamed dropDownList to dropDownListPseudo
Added "arrow.gif" as to be used the background-image for the combobox button
ua.css - added rules for select to differentiate between comboboxes and listboxes.
Added style rules to more closely match the XPTOOLKIT XPWidgets look.
removed the following :-moz-combobox-text, -moz-combobox-textselected
nsIFormControlFrame.h - Added SetSuggestedSize method.
nsButtonControlFrame - Implemented SetSuggestedSize.
nsCSSFrameConstructor.cpp - Rewrote ConstructSelectFrame.
nsIWidget.h -Added GetAbsoluteBounds method.
nsWindow.cpp - Implemented GetAbsoluteBounds.
The Mac now supports native combo box widgets so it no longer will crash in GetProperty
with a null mWidget field.
Modified nsComboboxControlFrame::HandleEvents. MouseExit from the combox rect now
initiates mouse capture on the drop-down list.
Modified nsCSSFrameConstructor::ConstructSelectFrame to initialize the drop-down list
for frame-based comboboxes as hidden.
Added a nsIListControlFrame::CaptureMouseEvents method.
Implemented nsListControlFrame::CaptureMouseEvents.