The rule of definite article "the"

I asked several questions about the definite article "the". Especially using "the" before user and mouse when describing an application was interesting to me.

I concluded it to myself that when I use "the", one can ask "which or who" and I should have an answer "the X which ...." based on the previous sentences, common knowledge, context.... You can consider it as the reader replies which

Let's give an example:

In the software, the user presses the left-button of the mouse and moves the mouse pointer on the main dialog box to draw a rectangle, then he fills the rectangle by choosing a color from the colors provided by the software on the right side ...."

Now:

Which software? The software we discussed in this article

Which User? any software has a user, and there is a user in front of computer, that user

Which mouse? any computer has one mouse, that mouse

Which button the left button of mouse (mmmm (or again the mouse?))

I think "mouse" doesn't need "the" here because it is general, if one asks which mouse? I can say any mouse

Which dialog box? the main dialog box, the one is shown first as you run an application

Which rectangle? The rectangle I already said about it, the one the user drew

Which colors? the colors provided by the software (it is in the sentence)

Which side? The right side, we have four sides I mean the right side

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Let's test it again!

In the morning when I wake up and see the sun in the sky, I thank the God for being alive to live another day.

Which morning ?, It's part of a day, the early part of day

Which sun ?, the sun, how many suns we have? I mean the sun

Which sky ?, the seventh sky! It's obvious, we have one sky

Which God, I didn't use "the" I strike it throw, however we have one God, but English don't say the God, then be careful with your rule

Could this rule work in practice?