Steps to reproduce the bug.
1) Create a Sprite object.
2) Create an image point.
3) Select the box with the X or the Y coordinate for the selected point.
4) Type a negative value (like "-20").
Effect: the image gets zoomed out when you press the minus keyboard button, instead of typing a negative value.
Currently, the only available way to set a negative value is either to click where the imagepoint should be or pressing the decrease value button until it reaches a negative number.
Suggestion: change the zoom shortcut to CTRL+plus or CTRL+minus.
Thanks for the attention,