This is one of many widget property panels you will encounter in GUI Pie. Each behave the same way. To understand each of the properties that might be displayed on these panels, check this section of the manual here.
Title. This is the unique title of a widget. It is also the name by which it is referenced in the code.
Text. This input field allows for the user to edit the text that will be displayed by the widget.
Colour. This changes the background colour of the widget, expressed as a 6-digit hex code.
Colour wheel button. This button opens a colour picker window, which allows for the most commonly used colours to be selected.
Text colour, Identical to above, just it changes the colour of the text (if applicable)
Font size - input field allowing user to input the font size for the text, written as a standard tkinter font size
Resize widget - a button allowing the user to redraw the widget. Once clicked, the widget will disappear and the grid will appear, allowing for the widget to be drawn again. If cancel is selected, the widget will return back to normal before the resize widget was selected
Apply - this applies the properties edited in the property panel to the screen. All changes are saved to file.
Cancel - this cancels all changes and maintains the state of the screen, without any edited properties.
Delete - this deletes the widget, removing it from the screen. This can be undone