I´m sorry because maybe it's a little late, but I'have just read this post.
To modify the buttons' icons you have to change buttons.gif file founding this file in "Arduino-master\build\shared\lib\theme" in the source code. The java file is EditorToolbar.java:
in this place you change the text when you rollover the icons in the same order than where placed each button (lines 39-47)
/** Rollover titles for each button. */
static final String title[] = {
_("Verify"), _("Upload"), _("New"), _("Open"), _("Save"), _("Serial Monitor")
};
/** Titles for each button when the shift key is pressed. */
static final String titleShift[] = {
_("Verify"), _("Upload Using Programmer"), _("New Editor Window"), _("Open in Another Window"), _("Save"), _("Serial Monitor")
};
You also have to eliminate the unused buttons from the list of buttons (lines 60-71)
static final int RUN = 0;
static final int EXPORT = 1;
static final int NEW = 2;
static final int OPEN = 3;
static final int SAVE = 4;
static final int SERIAL = 5;
static final int INACTIVE = 0;
static final int ROLLOVER = 1;
static final int ACTIVE = 2;
modify the buttons vector where are placed the buttons which are going to be loaded from buttons.gif (lines 102-112)
buttonCount = 0;
which = new int[BUTTON_COUNT];
//which[buttonCount++] = NOTHING;
which[buttonCount++] = RUN;
which[buttonCount++] = EXPORT;
which[buttonCount++] = NEW;
which[buttonCount++] = OPEN;
which[buttonCount++] = SAVE;
which[buttonCount++] = SERIAL;
And the function of each button it's defined in Editor.java... around line 1900 I think.
And this it's all, I think.
I'm trying to modify IDE too, trying to add some debugging options but I can't build it from eclipse... if you can see my post Problems running/ building Arduino IDE from Eclipse - Libraries - Arduino Forum I'll be very glad.
Bye!