fix wxPopupTransientWindow mouse events with GTK3, also fixes wxOwnerDrawnComboBox, wxDatePickerCtrl. closes #15874

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75687 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775