Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. TwinWave is a GtkPlug which manages two sessions of GTKWave in a single window. This allows for scrolling and other GUI manipulations to be performed in lockstep across both sessions. GtkPlug is the application-side endpoint used in the GTK implementation of the XEmbed protocol. The window to embed the application uses a GtkSocket. GTK+ (GIMP Toolkit) is a cross-platform widget toolkit for creating graphical user interfaces. It is one of the most popular toolkits for the X Window System, along with Qt.