Dotted Minim instead of tied notes?

[quote=“MarcLarcher”]When the options do not work, you always can override Dorico using Force duration (keystroke o or the c clamp in the left panel) and enter a dotted minim.

Thank you Marc!

So I tried what you suggested and still no result.

What I want is a minim to precede a quaver staccato. BUT in this image you will see a crotchet instead.
MINIM tied to a quaver.png
So the moment I turn the last crotchet note into a quaver staccato, it instantly reverts back to the tied crotchets before this note.
A minim.png
With regards to the O and L key commands, I clicked on my minims and pressed the L key to lock their value and then went to convert the crotchet into the quavers but it still reverted back to the tied crotchets.

Thank you for your assistance!