In smplayer 0.6.2 it's possible to configure the toolbars. That means that
now you can arrange the buttons and controls in the GUI the way you want.

For the moment the only way to do it is by editing the configuration file
(smplayer.ini). In a future version there'll be a graphical dialog for this.

In this document I'll try to explain what you have to change in order to
configure the toolbars the way you prefer.

Open smplayer.ini (~/.smplayer/smplayer.ini in linux, 
C:\Documents and Settings\your_username\.smplayer\smplayer.ini in windows) in
a text editor and look for these lines:

[default_gui]
actions\controlwidget=play, pause_and_frame_step, stop, separator, rewindbutton_action, timeslider_action, forwardbutton_action, separator, fullscreen, mute, volumeslider_action
actions\controlwidget_mini=play_or_pause, stop, separator, rewind1, timeslider_action, forward1, separator, mute, volumeslider_action
actions\floating_control=play, pause, stop, separator, rewindbutton_action, timeslider_action, forwardbutton_action, separator, fullscreen, mute, volumeslider_action, separator, timelabel_action
actions\toolbar1=open_file, open_dvd, open_url, separator, compact, fullscreen, separator, screenshot, separator, show_file_properties, show_playlist, show_preferences, separator, play_prev, play_next

As you can see this is a list of all "actions" that smplayer will display in
the toolbars.

actions\toolbar1 contains the list of actions in the main toolbar.
actions\controlwidget contains the list of actions in the controlbar.
actions\controlwidget_mini contains the list of actions in the small
controlbar that replaces the normal controlbar when the window is small.
And finally actions\floating_control contains the list of actions in the
floating control that appears in fullscreen mode.

You can remove, change the order or add new actions. The name of all available
actions can be seen in the shortcut editor, in Preferences->Keyboard and mouse.

Additionally you can also use the following actions:

 - timeslider_action : adds a time slider
 - volumeslider_action : adds a volume slider
 - timelabel_action : adds a label which shows the current playing time
 - rewindbutton_action : adds a button with a popup menu with all the rewind
   actions
 - forwardbutton_action : adds a button with a popup menu with all the
   forward actions
 - separator, adds a separator

You can also customize the mini GUI in the same way, just look for [mini_gui]
in the config file.

Important note: changes in smplayer.ini always have to be done when smplayer 
is NOT running!
