Allow to change the entry type for all selected entries simultaneously

[ThiloteE]

Is your suggestion for improvement related to a problem? Please describe.

1. Select multiple entries
2. Click
   • "entry type" here:
     
   • OR right-click on the selected entries and choose "change entry type"
3. Choose an entry type. E.g. article

Expected outcome:

All entries should have become "article".

Actual outcome:

Only one entry (the first entry) has switched its entry type and has become "article"

Describe the solution you'd like
Change the entry type for all entries, when multiple entries are selected.

Additional context:

• Apparently this was working in an older version of JabRef
• This issue was first raised in the forum here

[ThiloteE]

• The right click menu worked for me immediately. Worked 4/4 times. Once or twice I had to click twice at the entry type for it to have noticed me having clicked there I think. Not sure what is going there, but it definitely works well enough to use this.

• Clicking on this button
  
  unfortunately mostly did not. It worked once out of seven times I tried. I also had to double click a few times. Sometimes I only had to click once.

[ThiloteE]

Sometimes it only changes a few entries and MORE than one entry, but not all the entries that were selected.

I think I only have to click once on the button if I hit it more towards the left or to the far right. Not in the middle. I think there was a bug that reported this for Mac. Turns out this is also present on Windows.