Add tooltips to icon-only buttons

[imnasnainaec]

the icon-only buttons would benefit from a tooltip

[mikelothers]

Suggested tooltips:
Scroll to current reference
NOTE: When Continuous scroll is toggled on, the top horizontally-scrolling window does not scroll back to the current verse like the vertically-scrolling windows below it. It would be good to fix this.

Interlinear settings

Link to phrase

Unlink phrase
NOTE: Clicking this gives the user confirmation before unlinking the phrase. With the tooltip, confirmation may not be necessary. It isn't too difficult to redo the linking... and if Undo is supported, users would have that option to restore phrase linking as well.

Unlink phrase
NOTE: Clicking this does not get user confirmation before unlinking the phrase

Edit phrase

When entering phrase editing mode by clicking on the edit pencil, tooltips on the analyzed words may help the user have more confidence when editing the phrase. For example, when hovering over the analysis for pèche below, which is not included in the phrase, the tooltip could say something like "Add to phrase" or even "Add pèche to phrase"

...or when hovering over the analysis for pèche below, when it is already included in the phrase, the tooltip could say something like "Remove from phrase" or even "Remove pèche from phrase"

ves