Sadly, I can't test patches :(
Anyway, I have a further suggestion on the placement of options, and while that's not exactly your goal, it might still be the best time to do this.
First, I don't think there is enough space for "show all", "show obsolete", Filter and a search field. For example in German, "show obsolete" becomes "auch veraltete anzeigen". It could be shortened (zeige veraltete) but right above, there should be a currently empty line.
Furthermore, the function of "show all" is hard to grasp. There are several reasons why there would not be all vehicles visible - Filter, Search bar, timeline, electrification,... - none of which are affected by 'show all'. The only thing it DOES affect is whether vehicles that can currently be appended, put in front, or sold are the only vehicles to appear.
First line: Information about how many units are in the depot, and the sorting option to the very right.
Second line: The Append/Put in Front/Sell button. Next to it, the "show all" checkmark, since those two are thematically connected. Additionally, if possible, I'd invert it an change it's text to "show only appendable/sellable/...frontputable?" depending on the active option.
Third line: Start with the filter, then "show obsolete" and the search field. Note how all three options are filters, so they go well together, and using filter as the first element makes it lend it's name to the full line.
Edit: Does "prepend" work in this case for "put in front", making the checkmark "Show only prependable"?