In a similar vein, when I tap the right end of the expression in the screenshot below, the Pop-up definition immediately shows the definition for the entire expression, when with Pleco 3.2, it would start with a subexpression where I tapped.
I'd argue that selecting a sub-expression first is preferable, since the user already sees the definition for the full expression on the screen before tapping on anything. The exact rule set might look like this:
If the user taps the 问 character on the right end of the expression, there would be three possibilities: Selecting 为你是问, 是问, and 问. I think then, it should be 问 because selecting the longer 是问 might guess at the user's intentions too much and thus be confusing.
If the user taps on the 是 character in the second last position, there would be three possibilities, as well: Selecting 为你是问, 是问, and 是. Here, I think it would be most intuitive and ergonomic if 是问 were first selected, because it is different from the full expression and tells the user more about the meaning of the entire expression than just 是.
If the user taps on the second character, 你, it would be 你 because that's the only option. If there had been a definition for 你是 or 你是问, then that would be preferred over just 你.
If the user taps on 唯, I think 唯 would be best, because that's also the only option besides showing the entire expression. If there were a definition for 唯你, then that would be displayed first, as long as it's less long than the entire expression.
When the user taps on expressions in the Reader, then it's of course preferable to select and define expressions that are as long as possible towards both the right and the left using the Pop-up definition. In the case of Dictionary definitions, however, I think the behavior for the Pop-up definition should differ. In Legacy Pleco 3.2, it already did, but still not quite the way I tentatively suggest above.
That said, the selection handles have gotten more responsive with 4.0.
I searched for a related pop-up definition setting under Settings, but didn't chance on one.
Do you feel this might make sense?
Thanks,
Shun