Incorrect selection range and data loss can occur when selecting whole words with Ctrl+Shift + arrow keys

[nekohayo]

Convenience fork of issue #343, for your milestone-targetting purposes (for release notes etc.)

It was found that you can still get the latest version of Minder confused and lose some words when using various movements/insertions/deletions of words, under various circumstances, particularly when using Ctrl+Shift + arrow keys selection combos.

• First example with unexpected selections ranges: https://youtu.be/3etf8TVfrLo
• Another example with data loss: https://youtu.be/QzWTIt2NGww

If not already the case, it could be good to cover those various scenarios (and perhaps other stress-testing behavior I haven't thought of in the examples above) with automated tests, including the use of cut/copy/paste, backspace vs delete, undo/redo, etc.

[tomatic]

Note sure if it's related, but I thought I'd add this here rather than opening a new issue in case it is.

Using Ctrl+A to select node text and then deleting it causes the node to become uneditable until Minder is relaunched. Tested and 100 % reproducible with 1.14.0.

[phase1geo]

I know that the Control-A issue mentioned above has been fixed in the 1.15.5 release. I believe there still may be issues with the selection anchors used during selecting/editing text. Could you confirm this?