Increasing/Decreasing font size in ST-editors

How to increase or decrease the font size in the ST-editor (= how to zoom):

Press the keyboard combination Ctrl++ or Ctrl+- repeatedly until the font size is displayed with the requested size.
Mind that not only the current editor is affected but that the size is changed for all textual editors (such as an editor for PLC-object).

Be sure to press the key + or - on the keyboard and not the ones on the numeric keypad.
If you use the key + or - on the numeric keypad (when pressing the keyboard shortcuts Ctrl++ or Ctrl+-), the current code block is expanded or collapsed.