This happens when I create a horizontal or vertical line using the "shift" key, then try to resize the line using the selection tool and mouse.

This issue is present on InDesign 21.1 x64. My operating system is Windows 11. I have no InDesign Plugins installed.

I have experienced this issue on two different computers. The problem is not present on older versions of InDesign.

PROBLEM: When resizing a horizontal or vertical line, such as is created when holding down the 'shift' key, and that line has zero width, the line visually appears to change, then snaps back to its original length when the mouse is released.

If I attempt to change the length of the line using the "L:" box in the toolbar, a pop-up dialog box appears that says "Unable to set bounding box."

EXPECTED BEHAVIOR: The line changes size.

EXTRA INFO THAT MIGHT HELP:

If I create an angled zero-width line, it is resizable as expected, BUT if I rotate a horizontal or vertical zero width line, then attempt to resize, the resize fails with the same behavior.

If I change the width of the line to anything other than zero, I can resize the line as expected in all cases.

If I create a horizontal or vertical line with a width other than zero, I can resize the line, but if I change the width to zero, the line won't resize as described above.

It doesn't matter if I check or uncheck the "Constrain Proportions for Width and Height" toggle.

It doesn't matter if I check or uncheck the "Constrain Proportions for scaling" toggle.

If I hold down "shift" while resizing, the problem still exists.

If I hold down "ctrl" I can scale the line, which works for resizing

If I hold down "ctrl+shift" I can scale the line with fixed proportions, which does let me resize.

This get really weird when I try to resize a group of objects that contains zero width line. Sometime the resize fails, sometimes some part of the group change, but never the line. I don't have a consistent set of behaviors that I can describe when it comes to grouping.