The main idea is to make a connection between the size of the box and the size of the text thanks some 
                            There is 2 way to do that:
          
                    
                    Method1: The rectangle depends of the text
                              1) Right click over the size parameter of the 
                    Text renderer
                    Render a Text or group of text
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                     and create a 
                    Link
                    A link from a source parameter to a set of Link Target
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                     from the widht and the height
            
 
                    
                    
                              2) Drag and drop the width and the height parameters of the rectangle in the empty 
                    Link Target
                    Represent a link or parameter. Point toward an element parameter. "right click -> Goto" on the target to go to that element
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                              3) Right click on each 
                    Link Target
                    Represent a link or parameter. Point toward an element parameter. "right click -> Goto" on the target to go to that element
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                     and add a 
                    Divide
                    Divide the Input value
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                     for the height and the width.
           Set the divide value equals to the width resolution of your compo for the width.
           Do the same for the height. If your compo is 1920x1080, the 
                    Divide
                    Divide the Input value
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                               should have a divide value to 1920 for witdh.
            
 
                    
                              4) Select the 
                     Rectangle
                    A rectangle
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Rectangle
                    A rectangle
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                    , uncheck the scale->Linked paramters and link it's placement to the Text.
            
 
                    
                              5) In order to create some margin, go to the 
                    Link Target
                    Represent a link or parameter. Point toward an element parameter. "right click -> Goto" on the target to go to that element
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                     and add a 
                    Offset
                    Offset the input value with a simple - or + operator
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                    Method2: The text depends of the rectangle
                              Bit the same as the first method.
          
                              1) To be more intuitive, it's better to start this method with an anchor point for the text and rectangle at 0,0.
          
                              2) Create 
                    Link
                    A link from a source parameter to a set of Link Target
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                     from the width and the height placemenet paramters of the 
                     Rectangle
                    A rectangle
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Rectangle
                    A rectangle
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                              3) Select your 
                    Text Generator
                    A simple but very powerful text
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                     and in it's 
                    Text renderer
                    Render a Text or group of text
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                    , switch the width parameters from "auto" to "Word Wrap", such as its Height parameters from auto to clamp.
          
 
                    
                    
                              4) then, right click on the width and height parameter  of the text and connec to -> width or Height
          
                              5) Go to the placement options and link your text to the rectangle.
          
