All lists and widgets can be docked at any place or can be grouped together in a tab view.
If a widget is hidden, you can show it by selecting the View Menu from the menu bar.
All views can have their font-size set in the Preferences Dialog. In addtion, all list header support resizing, moving and hiding of columns. Columns are hidden / shown by right-clicking the list header element. All changes are persistent.
You can customize board and notation easily in the Preferences Dialog. Especially the notation can be changed to reflect your local standard. E.g., in Germany, the "Queen" is called "Dame" and thus represented by a "D" rather than a "Q". Change the piece letters in the Appearance tab of the Preferences. You can also change to a symblic representation of the pieces, provided you OS supplies the character sets used. That is the case with Mac OS X and Windows 7, untested with Linux. The PGN remains unchanged, it is defined with KQRBN.
Keyboard shortcuts are customized with the corresponding dialog from the Help menu. Please be careful, there is no checking for syntax errors or invalid entries, yet.
Note that the customization is associated with a language selection so you can have a different keyboard scheme with different languages.
Icons in menus can be enabled or disabled in the Preference dialog. Having icons in menus may help to get comforable with ChessX initially, lateron, you will probably do not want to have them in the menus.
Is it possible to import your own piece sets and board textures?
That would be a cool features people wanted.
See https://sourceforge.net/p/chessx/wiki/Reference/
A bit of manual fiddling, but it works