Rulers and Scale

[Guifan]

I have recently started using LibreOffice Draw for scale drawings but am experiencing some odd behavior.
If I change the scale via Tools>Options>General, selecting the required new scale from the drop down list and then clicking OK the ruler scales do not change. Despite this the objects I draw do appear at the dimensions expected.
For example, drawing a 5x5 square at scale of 1:1 shows as 5 units on both rulers and 5.00 x 5.00 on the Status bar. Changing scale to 1:2 causes no change to the rulers which still show the square as measuring 5 units but the Status bar shows the size correctly as 10 x 10.
By accident I discovered that hiding the side bar, if it is visible, or showing it, if it is hidden, triggers the rulers to change to the correct scale.
Is this a known bug or am I doing something wrong?

[RoryOF]

I think the change to the ruler occurs when one closes/reopens the Page pane, not the sidebar.

[Guifan]

I have done some further test and found that the ruler scale changes when either the Page pane or the Side bar are open/closed. I have also discovered that using any of the Zoom options also trigger the ruler scale change. There may other triggers but why doesn't the OK button on the Options - LibreOffice Draw - General dialog box do it?