There is an annoying bug when selecting the text: extending the selection is working incorrectly.
To reproduce:
1. Select a word with the mouse. Make sure the word is in the middle of the text. Select the characters from left to right
2. Now Shift+Left Arrow modifies the BEGINNING of the text, instead of the END.
Why is this a bug?
Open any other text editing software and see the difference: when selecting text with the mouse, the cursor is placed where the mouse button is released. If selecting from left to right, then pressing Shift+Arrow keys, will shrink/grow the selection AT THE END. Indesign is not following this rule, Shift+Arrows grow/shrink the BEGINNING of the text, despite, the mouse button was released at the end.

In indesign, selecting text often selects the whitespace after. Then the user tries to deselect the trailing whitespace by hitting Shift+Left arrow - bang, the leading white space is also selected!