The new default in Maple 2025 is to hide the Execution Group Boundaries in Worksheet mode.
In order to make them visible one has to use the menu

View > Show/Hide Contents > Execution Group Boundaries F9

or to press the F9 key.

The question: is there a method to have again visible boundaries by default? 

(Hiding the boundaries does not seem to be a good idea because an execution group can have (it is not clear why!) multiple prompts.)

f(a).b;            #ok
                           (f(a)) . b

op(0, f(a).b);     #ok
                               .

lprint(f(a).b);    #ok
f(a) . b

f(7).b;            #???
                             f(7) b

op(0, f(7).b);     #???
                               *

lprint(f(7).b);    #???
f(7)*b

This simple expression (from a recent post) crashes Maple:

simplify(tan(Pi/5) + sin(Pi/15) - sqrt(15));

In Maple 2025, in a new worksheet, this command crashes Maple; it is not possible to interrupt the computation (with the "Stop" button) and the worksheet must be closed.
In Maple 2024, the computation can be interrupted, but after repeating (maybe twice) the command, the interruption becomes impossible.

Question: is there a simpler command which crashes Maple?

It seems that the new Ribbon interface has several bugs (probably an update will come soon). So, not only the Export As is not working, but I see that (at least in Windows), opening a worksheet with a large output will display the output using the Maple input font.
Just save a .mw with the content:

expand((x+1)^200);

and then open it.

In the File menu,  the Export As dialog is missing. Only the default (.pdf) can be used; no .mpl or .tex)
The Save As dialog is incomplete (e.g. save to .mws).

Or, is the installation corrupted?