Yad - Yad (yet another dialog) is a fork of Zenity with many improvements, such as custom buttons...
Notepad++ - A free source code editor which supports several programming languages running under the MS Windows environment.
Glade - Glade is a RAD tool to enable quick & easy development of user interfaces for the GTK+ toolkit...
Notepad3 - Notepad3 is a fast and light-weight Scintilla-based text editor with syntax highlighting.
wxFormBuilder - wxWidgets is an excellent framework that enables the creation of multi-platform applications with...
TED Notepad - TED Notepad is a portable text editor software that deals with a large variety of text processing tools, supplemental text clipboards, high accessibility through hotkeys, and a customizable number of settings and options.