The best replacement for wxwidgets is qt.

The best alternatives to wxwidgets are rated as following:
★★★★★  qt
★★★  gtk
★★  mfc
★★  wxpython
★  tkinter
★  qt python
★  gtkmm
★  win32
★  fltk
★  winapi
  qt4
  gtk+
  pyqt
  wxsmith
  windows api

Your alternative for wxwidgets is not listed? Suggest!
Speaking about wxwidgets, one probably shouldn't forget about codeblocks.

Other search terms related to wxwidgets and their ratings are:
★★★★★ codeblocks
★★★ code blocks
★ implement_app
You have in mind a companion for wxwidgets and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of wxwidgets in all years. Click on graph for more.
wxwidgets
qt
gtk