My tabs (horizontal) have suddenly started appearing in the tab in the reverse order with the more recent at the left instead of the right

I have horizontal tabs in Firefox 152.0.4 on a Macbook with Tahoe 26.5.1. My tabs have suddenly reversed order, so that the most recent ones are at the left and the older ones towards the right. Strangely, if I open a new tab it appears to the right of the current tab. I tried closing Firefox and reopening, but it did not change anything. Is there a way to restore usual order of tabs so that the newer ones are at the right?