Summary: You can now simple select “Fit Box to Text” to fit box to the text vertically when space is available in the text box or when there is a text overflow in a text box.
Solution:
In a textbox filled with text if still some space is left the text can be adjusted so that the text fits in the box. This also applies when the text reflows in a textbox
The option is available in Item menu and in Context Menu when text box is selected either with content or item tool.
Fit Box to Text works with all shapes of text boxes including multi-column text boxes. However, it will resize the boxes vertically only.
For linked (or automatic) text boxes, Fit Box to Text applies to only selected box on the current page and removes any empty space/gap after the last line.