Interface elements:

• File
  Contains the path to the file from which the button icon will be loaded.
  
  
• Index
  Contains the index number of the icon in the file specified in the "File" parameter.
  
  
• Use negative index
  The negative index value of the icon in the file is used if the option is enabled.
  
  
• «OK» button
  Confirms changing the icon of the selected button.
  
  
• «Cancel» button
  Doesn't confirm changing the icon of the selected button.
  
  

Hotkeys:

1. Alt + F4
   Pressing this hotkey closes button icon window without applying button icon changes.
   
   
2. Enter
   Pressing this hotkey applies button icon changes and closes button icon window.
   
   
3. Esc
   Pressing this hotkey closes button icon window without applying button icon changes.