[LyX/2.1.x] Fix wrong indentation on screen.

[Enrico Forestieri]

commit 956f50340144370fac4e76d4d500bbcf55e23e29
Author: Enrico Forestieri <for...@lyx.org>
Date:   Wed May 21 23:59:53 2014 +0200

    Fix wrong indentation on screen.
    
    LyX fails to indent on screen a standard paragraph when it is
    nested into an environment. The fix is a one-liner but the diff
    is larger because it also fixes a previous wrong indentantion
    in the source ;)
    
    No status line needed because this is an extension of f5a246b1.

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 9e34839..9635388 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -1905,10 +1905,11 @@ int TextMetrics::leftMargin(int max_width,
 
        // This happens after sections or environments in standard classes.
        // We have to check the previous layout at same depth.
-       if (tclass.isDefaultLayout(par.layout()) && pit > 0) {
-           pit_type prev = text_->depthHook(pit, par.getDepth());
-           if (pars[prev < pit ? prev : pit - 1].layout().nextnoindent)
-                   parindent.erase();
+       if (tclass.isDefaultLayout(par.layout()) && pit > 0
+           && pars[pit - 1].getDepth() >= par.getDepth()) {
+               pit_type prev = text_->depthHook(pit, par.getDepth());
+               if (pars[prev < pit ? prev : pit - 1].layout().nextnoindent)
+                       parindent.erase();
        }
 
        FontInfo const labelfont = text_->labelFont(par);