Issue/annoyance

It's also important to keep in mind that while this is the English-speaking forum, not everyone who volunteers their time to assist here is a native English speaker. FWIW, I am, but to me, "pixel pitch" suggests distance between things, so I was guessing you might have meant the distance between two liens of text. MuseScore has never provided that before, but in our constant effort to improve the program and add more and more flexibility, version 3.6 will now provide this ability.

The Inspector in previous versions was very limited, now it is far more powerful and flexible, able to do things that previously could only be done more clumsily via right-click menu and separate modal dialogs that prevented you from working with the score while the dialog was open.

As for "Text Edit", there is no such entry in the right-click menu. Maybe you mean "Edit Element"? This hasn't changed, it does what it always has - it puts the element in edit mode. For text, that means giving you a cursor so you can literally edit the text - type new letter, delete old ones, etc. It has nothing to do with any properties of the text like visibility or size. Basically, "Edit Element" is just the same as double-click. Again in the interest of flexibility, we provide both ways of accessing edit mode.

I have no idea, though, what you mean by "window for midi tempo". There is no such window I am aware of.

What is supposed to happen when you move your mouse over an existing note/chord you get the preview note (mine is blue but I don't remember if I customized it) showing where the note will be entered. If you have a note there already it should add a note to the chord. Sensitivity is a consideration. If you don't have a steady hand it's possible to move the mouse to the left a little and accidentally add a note to the previous chord rather than where you want it.

As for accidentals, what someone previously tried to explain (and might have been able to do it better) is that since about version 3.3 you have needed to click the accidental button on the toolbar before you add a note. Prior to that, you added a note then clicked the toolbar to add the accidental. This change was not clearly explained so it is possible you didn't know about it. So you know, a lot of people complained because when they wanted a G# they had to enter a G hear that note then click the accidental and hear that note. The request was very reasonable and the change is actually more logical. It totally messed up my workflow though, so I'm glad you can now define shortcuts that will apply accidentals after note entry if you prefer.

Remember, I don't know what you know about the program and music in general, so if I tell you something you know take it as too much information on my part. When you enter a note without an accidental it will always follow the key signature if it's the first occurrence of the note on that staff or it will be assume the same accidental of the note of the same pitch previously entered. This means that if you have an F# (and no E#) in the key signature, the first time you enter an F in a measure you get an F#. The status bar at the bottom left of the MuseScore window will confirm this. If you want an F natural you can either apply an accidental or press the down arrow to change the pitch. If you do this, the next F you enter in that measure will be an F natural by default with no accidental necessary and pressing arrows will change it to either an F# (with an accidental) if you press up or an E if you press down. It is possible that this is what you are having a problem with in regards to the naturals. I originally assumed you knew this and the problem was likely with your mouse. Since it's so new, it's not likely (but not impossible) to be the mouse so there must be something you are not understanding about how the program works.

R.L.F. I've had the occasional problem with using the mouse alone when entering notes. But I suspect it had mostly to do with the level of magnification in MuseScore and/or the sensitivity of my mouse. I found I got much better (i.e. accurate with what I wanted to do) note entry by increasing the view size to e.g. 150% via 'View - Zoom In' or entry of '150' into the page size text box at the top of the screen. It's not necessarily a fix for your issue, but if you have no success with the other tips, you may want to try this technique.