As I recall, select shape and adding arrow heads will apply to just dimension lines and not the alignment lines.
Apparently, the dimension shapes are actually 2 lines. So if I add arrowheads, it looks like this:
I have no idea why that might be. My guess is some software nerd made some shortcutting decision. It reminds me of the time I was working on the microcode for an early ATM machine. Memory was scarce, so we tried to keep usage down. We would not use a full word (32 bits) if a half-word would do (16 bits). These early ATMs had bills in 2 denominations, say $20s and $5s. So if the customer wanted to withdraw $100, they could ask for 5 $20s, 4 $20s & 4 $5s, 3 $20s and 8 $5s, etc.
We needed a way for the code to know if one of the hoppers ran out, so it could only dispense the other denomination. The guy writing the allocation code was famous for the tightest, and most difficult to follow, code anywhere. The logical thing to do would be to have a 1 bit flag for each hopper indicating whether it had bills or not. This guy came up with an algorithm that saved several bytes of code, and the 1 bit flags, by using the sign bit to indicate whether the hopper had bills or not. If the value was positive, it meant the hopper had bills. When it ran out, the code would set that value to negative. So a value of +20 meant that it had $20 bills. A value of -20 meant that it held $20s, but it was out.
This worked pretty well until the first ATM was installed in Italy. The most common bill there was the 50,000 Lira. When we were using a full half word, 16 bits, it could register a number from 0 - 65,535. But when the first bit was used for a sign bit, the range was reduced to 0 - 32,767, which could not handle 50,000. So we had to ship special software to Italy until the next release. 🙄😯
