I am using ubuntu MATE 22.04, with version 21.10.0-1 of the mate-dock-applet. I've removed all the window managers from my panel, so the Dock has plenty of space. But it seems to be limited to showing only 10 icons. So, when I have more than 10 apps open at a time, I have to scroll back and forth... a lot! And the delay before the scroll starts is sometime longer than I have patience for!
I have looked thru the prefs in the dconf editor (/org / mate / panel / objects / object-N) - the option "dock-fixed-size" seems like it might be the ticket. It's values range from -LONGMAX to +LONGMAX and defaults to -1. I've tried a number of values, including +LONGMAX, but it doesn't make any difference. I've also poked around in the various "panel" options, tweaking a few numeric values, but still no joy.
How can I increase the width of the Dock applet, or the width the panel will grant to it?!?