(with single file TW 5.1.17, latest FF)
If you see tiddlers starting with "class=--" followed by numbers-- they seem to be created by tabs macros that don't have a state tiddler defined-- yes, I was sloppy with the coding. They will appear in the list of the "Recent" tab and their text field will contain the title of a tiddler selected by the tabs macro.
These tiddlers are normal tiddlers (a non shadow tiddler in its tiddler "Info", "Advanced" tab), will appear in the "Recent" tab, in the "More" tab, "All" section, and will appear in search results for "class=--" in the normal search bar.
The "class" of the title possibly comes from the tabs macro-- one of its parameters is "class".
I've had other similarly named unknown tiddlers -- like "details=--" appear, all having the same "=--" section and I assume they're created by macros where I didn't properly set a state parameter.
If you have multiple tab macros in your TW, be sure to use unique state tiddler names for each (see below) or they will share the same state and one tab macro will show the seelected tab from a previously used tab macro
If you want to keep track of the names you use for state tiddlers the "More" tab, "Explorer" section, "state/" folder lists all state tiddlers. "$:/state/tab--" tiddlers also seem to be created by tab macros with no unique state tiddler declared.
Or you can use the filter expression in "Advanced Search":
[prefix[$:/state]!prefix[$:/state/edit]!prefix[$:/state/folded]!prefix[$:/state/toc]!prefix[$:/state/tree]]
Or in a tiddler, use this list which will also display the "text" fields of each tab state tiddler
<$list filter="[prefix[$:/state]!prefix[$:/state/edit]!prefix[$:/state/folded]!prefix[$:/state/toc]!prefix[$:/state/tree]]">
<$link><$view field="title"/></$link> -- <$view field="text"/><br/>
</$list>
quirks of the tabs macro (covered by an older thread)
if you use "tc-vertical"/class="tc-vertical" instead of the default horizontal tabs which don't need any declaration, there's particular ways to do it, where it had to be the fourth "" parameter (parameter names not needed)-- ie you must have 3 sets of "" (filled or empty) before it
<<tabs "tabList" "$:/state/tabsuniquesuffix" "_default tab name_" "tc-vertical">>
<<tabs "tabList" "$:/state/tabsuniquesuffix" "" "tc-vertical">>
these don't work, the tab macro will work but not display vertically
<<tabs "tabList" "_state tiddler title_" "tc-vertical">>
<<tabs "tabList" "_default tab name_" "tc-vertical">>
amusingly these typos worked
<<tabs "tabList" "_state tiddler title_" ""tc-vertical>>
<<tabs "tabList" "_state tiddler title_" ;;"tc-vertical">>
<<tabs "tabList" "_state tiddler title_" ""tc-vertical">>