At startup, Geany loads the 15 first files from the last time, Geany was launched. You can disable this feature in the settings dialog(see Figure 3.2, “General tab in preferences dialog”). If you specify some files on the commandline, only these files will be opened. But you can find the files from the last session in the file menu. There is an item "Recent files". It contains the last 15 recently opened files.

If a C file(with extension is c, cpp, h, etc.) is opened, a global tags file is loaded once, which contains many function declarations from the glibc and some other libraries, like X, Bonobo, Gnome, GTK, Glib and so on. These declarations are used for call tips and auto completion. These tags are only useful if you are writing C or C++ source code. So if you know, that you don't need these things, you can skip loading this tag file. To do so, start Geany with the argument "-n" or "--no-ctags", for more information see the section called “Commandline options”.