How to reset the size of the Qt's window font?

Question

I have left my computer on overnight and in the morning I have noticed, that the font of the windows in QtCreator is significantly bigger as it was, though not everywhere. The text editor, the menu and the side panels are shown with the usual font size (see the first screenshot). I have also noticed, that this change affects other Qt programs, as the Maintenance tool and QtLinguist.

Legend: Red - huge font, should be reset. Green - font is as it should be.

The font size of all other installed programs is unchanged. Just in case I have checked the display settings of Windows and the scale is at 100%, where it was.

Note: I have tried deleting the settings under user/AppData..., but it didn't help.

How to reset the font back to normal?

Answer 1

for changing the size of the font in the source code you can use the short cuts (with the editor focused)

to zoom in: "ctrl" and "+"

to zoom out: "ctrl" and "-"

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for the environment the you can set the environment variable

export QT_SCALE_FACTOR=1.5