diff --git a/RichString.c b/RichString.c
index 556674b0d..248b3ae04 100644
--- a/RichString.c
+++ b/RichString.c
@@ -9,7 +9,9 @@ in the source distribution for its full text.
 
 #include "RichString.h"
 
+#include <assert.h>
 #include <ctype.h>
+#include <limits.h> // IWYU pragma: keep
 #include <stdlib.h>
 #include <string.h>
 
@@ -144,7 +146,8 @@ static inline int RichString_writeFromAscii(RichString* this, int attrs, const c
    int newLen = from + len;
    RichString_setLen(this, newLen);
    for (int i = from, j = 0; i < newLen; i++, j++) {
-      this->chptr[i] = (CharType) { .attr = attrs & 0xffffff, .chars = { (isprint(data[j]) ? data[j] : L'\xFFFD') } };
+      assert((unsigned char)data[j] <= SCHAR_MAX);
+      this->chptr[i] = (CharType) { .attr = attrs & 0xffffff, .chars = { (isprint((unsigned char)data[j]) ? data[j] : L'\xFFFD') } };
    }
 
    return len;
diff --git a/Settings.c b/Settings.c
index 07b7e6a28..5913af27a 100644
--- a/Settings.c
+++ b/Settings.c
@@ -233,7 +233,7 @@ static const char* toFieldName(Hashtable* columns, int id, bool* enabled) {
 }
 
 static int toFieldIndex(Hashtable* columns, const char* str) {
-   if (isdigit(str[0])) {
+   if (isdigit((unsigned char)str[0])) {
       // This "+1" is for compatibility with the older enum format.
       int id = atoi(str) + 1;
       if (toFieldName(columns, id, NULL)) {
diff --git a/linux/LinuxProcess.c b/linux/LinuxProcess.c
index 741fe19dc..e70d7d0c9 100644
--- a/linux/LinuxProcess.c
+++ b/linux/LinuxProcess.c
@@ -284,9 +284,18 @@ static void LinuxProcess_rowWriteField(const Row* super, RichString* str, Proces
    #ifdef HAVE_VSERVER
    case VXID: xSnprintf(buffer, n, "%5u ", lp->vxid); break;
    #endif
-   case CGROUP: xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CGROUP], Row_fieldWidths[CGROUP], lp->cgroup ? lp->cgroup : "N/A"); break;
-   case CCGROUP: xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CCGROUP], Row_fieldWidths[CCGROUP], lp->cgroup_short ? lp->cgroup_short : (lp->cgroup ? lp->cgroup : "N/A")); break;
-   case CONTAINER: xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CONTAINER], Row_fieldWidths[CONTAINER], lp->container_short ? lp->container_short : "N/A"); break;
+   case CGROUP:
+      xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CGROUP], Row_fieldWidths[CGROUP], lp->cgroup ? lp->cgroup : "N/A");
+      RichString_appendWide(str, attr, buffer);
+      return;
+   case CCGROUP:
+      xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CCGROUP], Row_fieldWidths[CCGROUP], lp->cgroup_short ? lp->cgroup_short : (lp->cgroup ? lp->cgroup : "N/A"));
+      RichString_appendWide(str, attr, buffer);
+      return;
+   case CONTAINER:
+      xSnprintf(buffer, n, "%-*.*s ", Row_fieldWidths[CONTAINER], Row_fieldWidths[CONTAINER], lp->container_short ? lp->container_short : "N/A");
+      RichString_appendWide(str, attr, buffer);
+      return;
    case OOM: xSnprintf(buffer, n, "%4u ", lp->oom); break;
    case IO_PRIORITY: {
       int klass = IOPriority_class(lp->ioPriority);
@@ -317,7 +326,10 @@ static void LinuxProcess_rowWriteField(const Row* super, RichString* str, Proces
       }
       xSnprintf(buffer, n, "%5lu ", lp->ctxt_diff);
       break;
-   case SECATTR: snprintf(buffer, n, "%-*.*s ", Row_fieldWidths[SECATTR], Row_fieldWidths[SECATTR], lp->secattr ? lp->secattr : "N/A"); break;
+   case SECATTR:
+      snprintf(buffer, n, "%-*.*s ", Row_fieldWidths[SECATTR], Row_fieldWidths[SECATTR], lp->secattr ? lp->secattr : "N/A");
+      RichString_appendWide(str, attr, buffer);
+      return;
    case AUTOGROUP_ID:
       if (lp->autogroup_id != -1) {
          xSnprintf(buffer, n, "%4ld ", lp->autogroup_id);