This matter of horizontal rules has come up before on this forum in February and March. The March answer contains some decent links. I think the main aspects to this issue are: a) you cannot please everyone; b) The term “horizontal rule” is used generically to refer to several different types of line, each accessed via differing methods; c) the v4.0 release notes did not advise of this change.
Methods for inserting a horizontal line: There are several ways of creating a horizontal line in a Writer document. In the v3.5-3.6 series there were four ways:
- Automatic conversion of three special characters into a paragraph style border (lower edge).
- Direct application of the Horizontal Line paragraph style.
- Using the Drawing toolbar Line button.
- Inserting a graphic object (GIF) from the gallery.
In the v4.0 series the last of these methods has been dropped (at least for now). As the March thread above indicates, an associated bug (FDO#60858) points to the commit in question and provides a basic rationale for the change. It may come back, but even if it does you need to prepare yourself for the possibility that the gallery facility could potentially change in future releases anyway.
Gallery update: There has long been a desire to update the gallery artwork (FDO#36947) and possibly even replace the entire gallery facility with an alternative (FDO#30744). I tend to agree that the current artwork is dated and that a newer source of clipart would be welcome, however this may cause legacy issues for others (such as yourself) that have make use of the existing artwork. At the very least I feel the gallery should make use of clipart in PNG format in preference to GIF.
Help pages: By way of comparison (to the methods listed above), the old help page on inserting a horizontal line mentions the “plain” (paragraph style) and the “graphical” (galley object) types of horizontal line. All three AskLO threads deal with the graphical object type. The new help page on drawing lines in text indicates (by ommission) how the gallery facility (and corresponding menu option) has been dropped. It also includes a warning that applies only to graphical objects and is true for even the v3.5-3.6 series:
The lines and other drawing objects that you insert in text are not defined in HTML, and are therefore not exported directly into HTML format. Instead, they are exported as graphics.
Note that the third method I mentioned (Drawing element) does not export to HTML at all.
<hr> element: The prior warning is doubly important because there is a tendency to associate the term “horizontal rule” with the HTML
<hr> element. LO does not generate this HTML element, either in ODT XML or when exporting to HTML, regardless of the type of horizontal rule used. This, and the preference to use styles in deference to graphic objects may also have influenced the decision to remove the Insert > Horizontal Rule… menu option and associated gallery.
Portability of styles: The decision may also relate to the fact that paragraph styles (from an editing point of view) are more portable than gallery objects.